WEBVTT 00:00:00.000 --> 00:00:00.978 align:middle line:90% 00:00:00.978 --> 00:00:02.445 align:middle line:90% [SQUEAKING] 00:00:02.445 --> 00:00:04.401 align:middle line:90% [RUSTLING] 00:00:04.401 --> 00:00:05.868 align:middle line:90% [CLICKING] 00:00:05.868 --> 00:00:13.665 align:middle line:90% 00:00:13.665 --> 00:00:16.040 align:middle line:84% MICHAEL CUTHBERT: I'm going to switch over to the Jupyter 00:00:16.040 --> 00:00:20.460 align:middle line:84% Notebook to talk a review of last class, 00:00:20.460 --> 00:00:21.900 align:middle line:90% and then going forward. 00:00:21.900 --> 00:00:25.380 align:middle line:84% So what are some of the things we unlocked last class? 00:00:25.380 --> 00:00:29.300 align:middle line:84% So Music21 objects that we can use. 00:00:29.300 --> 00:00:32.540 align:middle line:90% Shout them out. 00:00:32.540 --> 00:00:33.170 align:middle line:90% What's that? 00:00:33.170 --> 00:00:33.870 align:middle line:90% Stream. 00:00:33.870 --> 00:00:34.520 align:middle line:90% Good. 00:00:34.520 --> 00:00:34.932 align:middle line:90% AUDIENCE: Pitch. 00:00:34.932 --> 00:00:35.640 align:middle line:90% AUDIENCE: Corpus. 00:00:35.640 --> 00:00:37.700 align:middle line:84% MICHAEL CUTHBERT: Pitch, corpus, I heard. 00:00:37.700 --> 00:00:38.538 align:middle line:90% Anything else? 00:00:38.538 --> 00:00:39.330 align:middle line:90% AUDIENCE: Duration? 00:00:39.330 --> 00:00:40.455 align:middle line:90% MICHAEL CUTHBERT: Duration. 00:00:40.455 --> 00:00:43.525 align:middle line:84% And pitch from duration lets you do what? 00:00:43.525 --> 00:00:44.150 align:middle line:90% AUDIENCE: Note. 00:00:44.150 --> 00:00:44.910 align:middle line:90% MICHAEL CUTHBERT: Note, good. 00:00:44.910 --> 00:00:45.660 align:middle line:90% We remember that. 00:00:45.660 --> 00:00:48.090 align:middle line:84% And there's one other one I just want to remind you. 00:00:48.090 --> 00:00:49.590 align:middle line:84% We're not going to use it very much. 00:00:49.590 --> 00:00:50.850 align:middle line:90% It's called converter. 00:00:50.850 --> 00:00:52.392 align:middle line:84% Let me make this a little bit bigger. 00:00:52.392 --> 00:00:54.110 align:middle line:90% Oh, that's nice for me, too. 00:00:54.110 --> 00:00:57.890 align:middle line:90% And sorry. 00:00:57.890 --> 00:01:00.530 align:middle line:90% Great. 00:01:00.530 --> 00:01:03.020 align:middle line:84% Because converter does the same thing as corpus, but loads 00:01:03.020 --> 00:01:07.260 align:middle line:84% any file on your hard drive or anywhere on the web. 00:01:07.260 --> 00:01:11.130 align:middle line:84% But since I don't know what's on your hard drive, 00:01:11.130 --> 00:01:13.220 align:middle line:84% we're not going to use it that much. 00:01:13.220 --> 00:01:15.620 align:middle line:90% Great. 00:01:15.620 --> 00:01:18.840 align:middle line:84% And what's something we did last class? 00:01:18.840 --> 00:01:19.940 align:middle line:90% What's the problem? 00:01:19.940 --> 00:01:23.790 align:middle line:84% So let's all load that Bach piece. 00:01:23.790 --> 00:01:25.532 align:middle line:84% Anyone remember what I should type? 00:01:25.532 --> 00:01:26.240 align:middle line:90% AUDIENCE: Corpus. 00:01:26.240 --> 00:01:27.703 align:middle line:90% MICHAEL CUTHBERT: Corpus dot-- 00:01:27.703 --> 00:01:28.370 align:middle line:90% AUDIENCE: Parse. 00:01:28.370 --> 00:01:29.090 align:middle line:90% MICHAEL CUTHBERT: Parse. 00:01:29.090 --> 00:01:29.730 align:middle line:90% Good. 00:01:29.730 --> 00:01:35.160 align:middle line:90% And I said it was Bach BWV 66.6. 00:01:35.160 --> 00:01:36.860 align:middle line:84% The only thing you actually need is 00:01:36.860 --> 00:01:38.810 align:middle line:84% whatever is necessary to distinguish it 00:01:38.810 --> 00:01:41.000 align:middle line:90% from anything else. 00:01:41.000 --> 00:01:43.460 align:middle line:84% So you'll sometimes see I'm going 00:01:43.460 --> 00:01:44.850 align:middle line:90% to be taking a shortcut there. 00:01:44.850 --> 00:01:45.920 align:middle line:90% Good. 00:01:45.920 --> 00:01:48.570 align:middle line:84% And how many things were in Bach? 00:01:48.570 --> 00:01:49.320 align:middle line:90% Do you remember? 00:01:49.320 --> 00:01:49.820 align:middle line:90% Estimate. 00:01:49.820 --> 00:01:50.470 align:middle line:90% Six. 00:01:50.470 --> 00:01:50.970 align:middle line:90% Oh, good. 00:01:50.970 --> 00:01:52.170 align:middle line:90% We have the exact number. 00:01:52.170 --> 00:01:52.910 align:middle line:90% Yep. 00:01:52.910 --> 00:01:55.430 align:middle line:90% Why? 00:01:55.430 --> 00:01:58.170 align:middle line:90% Where are the notes? 00:01:58.170 --> 00:02:03.030 align:middle line:84% We have a score object, I'm pretty sure, just to recall. 00:02:03.030 --> 00:02:05.070 align:middle line:90% Yep. 00:02:05.070 --> 00:02:06.520 align:middle line:90% We have score object. 00:02:06.520 --> 00:02:09.460 align:middle line:84% And then what's inside of it, the main thing, 00:02:09.460 --> 00:02:11.753 align:middle line:90% four of the six things? 00:02:11.753 --> 00:02:12.420 align:middle line:90% AUDIENCE: Parts. 00:02:12.420 --> 00:02:13.670 align:middle line:90% MICHAEL CUTHBERT: Parts, good. 00:02:13.670 --> 00:02:15.410 align:middle line:84% And then inside the part, Hannah, 00:02:15.410 --> 00:02:17.410 align:middle line:84% did you-- you had your hand up for the last one. 00:02:17.410 --> 00:02:18.180 align:middle line:90% I'll get you in. 00:02:18.180 --> 00:02:19.973 align:middle line:90% What's inside of a part? 00:02:19.973 --> 00:02:20.890 align:middle line:90% AUDIENCE: The measure? 00:02:20.890 --> 00:02:21.940 align:middle line:84% MICHAEL CUTHBERT: Measure objects. 00:02:21.940 --> 00:02:22.440 align:middle line:90% Good. 00:02:22.440 --> 00:02:25.463 align:middle line:84% And what's inside the measure objects? 00:02:25.463 --> 00:02:26.130 align:middle line:90% AUDIENCE: Notes? 00:02:26.130 --> 00:02:28.660 align:middle line:84% MICHAEL CUTHBERT: Notes, and other things, but primarily. 00:02:28.660 --> 00:02:31.780 align:middle line:84% So we have this hierarchy, this nested hierarchy. 00:02:31.780 --> 00:02:36.760 align:middle line:90% Score, parts, measure, notes. 00:02:36.760 --> 00:02:40.990 align:middle line:84% There may sometimes even be another level of hierarchy. 00:02:40.990 --> 00:02:44.130 align:middle line:84% For instance, in scores like this 00:02:44.130 --> 00:02:50.340 align:middle line:84% where you have two different voices on the same part, there-- 00:02:50.340 --> 00:02:51.220 align:middle line:90% what do you call it? 00:02:51.220 --> 00:02:54.370 align:middle line:84% There may be a voice object inside of a measure. 00:02:54.370 --> 00:02:56.930 align:middle line:84% And if you have a whole collection of scores, 00:02:56.930 --> 00:03:00.105 align:middle line:84% we call it something begins with an O-P. 00:03:00.105 --> 00:03:00.730 align:middle line:90% AUDIENCE: Opus. 00:03:00.730 --> 00:03:01.450 align:middle line:90% MICHAEL CUTHBERT: Opus, yeah. 00:03:01.450 --> 00:03:04.010 align:middle line:84% So you can have something that's bigger than a score. 00:03:04.010 --> 00:03:06.670 align:middle line:84% You can have opuses, opera, technically, 00:03:06.670 --> 00:03:09.380 align:middle line:84% an opus that has scores inside it. 00:03:09.380 --> 00:03:11.570 align:middle line:84% And then you can put opuses inside opuses, 00:03:11.570 --> 00:03:12.950 align:middle line:84% because I didn't want to make anything bigger. 00:03:12.950 --> 00:03:13.720 align:middle line:90% Yeah, go ahead, Misha. 00:03:13.720 --> 00:03:14.350 align:middle line:90% AUDIENCE: Can we close the door? 00:03:14.350 --> 00:03:15.380 align:middle line:84% MICHAEL CUTHBERT: Oh yeah, sure, sure. 00:03:15.380 --> 00:03:17.630 align:middle line:84% Can you close the door for somebody who can get there? 00:03:17.630 --> 00:03:20.150 align:middle line:90% Thanks. 00:03:20.150 --> 00:03:23.410 align:middle line:90% Thank you, I appreciate it. 00:03:23.410 --> 00:03:24.130 align:middle line:90% Great. 00:03:24.130 --> 00:03:29.350 align:middle line:90% So how did we get down to the-- 00:03:29.350 --> 00:03:32.110 align:middle line:84% how did we get down to the notes last time? 00:03:32.110 --> 00:03:36.882 align:middle line:84% We did something like four thing in score. 00:03:36.882 --> 00:03:37.840 align:middle line:90% You don't have to type. 00:03:37.840 --> 00:03:38.890 align:middle line:90% This as all review. 00:03:38.890 --> 00:03:44.230 align:middle line:90% In Bach if thing, in if-- 00:03:44.230 --> 00:03:48.550 align:middle line:84% we remember that isinstance is the Python way of figuring out 00:03:48.550 --> 00:03:53.390 align:middle line:84% same thing in score is a stream dot part. 00:03:53.390 --> 00:03:55.610 align:middle line:84% We can also just say stream dot stream. 00:03:55.610 --> 00:04:01.930 align:middle line:84% If it's some of a stream, then for thing in part in thing 00:04:01.930 --> 00:04:04.120 align:middle line:90% in score. 00:04:04.120 --> 00:04:06.430 align:middle line:84% I don't want to waste too much time on this. 00:04:06.430 --> 00:04:09.970 align:middle line:90% I can do this. 00:04:09.970 --> 00:04:12.350 align:middle line:90% If instance thing in part. 00:04:12.350 --> 00:04:14.980 align:middle line:84% Somebody tell me if I type something wrong on this, 00:04:14.980 --> 00:04:16.339 align:middle line:90% because I'll probably do it. 00:04:16.339 --> 00:04:19.750 align:middle line:90% And there's no tricks on this. 00:04:19.750 --> 00:04:25.840 align:middle line:90% For thing in-- what is it? 00:04:25.840 --> 00:04:34.070 align:middle line:84% Measure in thing in part, print thing in measure. 00:04:34.070 --> 00:04:35.560 align:middle line:90% Hopefully, that works. 00:04:35.560 --> 00:04:36.640 align:middle line:90% Yep. 00:04:36.640 --> 00:04:39.190 align:middle line:84% So that lets us get down to the lowest 00:04:39.190 --> 00:04:44.350 align:middle line:90% level of what's happening here. 00:04:44.350 --> 00:04:46.330 align:middle line:90% We have a whole bunch of notes. 00:04:46.330 --> 00:04:47.210 align:middle line:90% What are we doing? 00:04:47.210 --> 00:04:50.630 align:middle line:90% 00:04:50.630 --> 00:04:53.860 align:middle line:84% You'll remember the two representations, the box 00:04:53.860 --> 00:04:58.660 align:middle line:84% representation or the salami slice, time wise. 00:04:58.660 --> 00:04:59.810 align:middle line:90% What are we doing? 00:04:59.810 --> 00:05:02.450 align:middle line:84% Are we going through all the parts here first, 00:05:02.450 --> 00:05:06.290 align:middle line:84% or are we going through one part and then another? 00:05:06.290 --> 00:05:06.790 align:middle line:90% Hint. 00:05:06.790 --> 00:05:08.540 align:middle line:84% You can always look back at your score. 00:05:08.540 --> 00:05:10.935 align:middle line:84% You know the piece and you have the notes. 00:05:10.935 --> 00:05:18.070 align:middle line:90% 00:05:18.070 --> 00:05:18.680 align:middle line:90% Go ahead. 00:05:18.680 --> 00:05:23.772 align:middle line:84% And when you have it, just look up and then shout it out. 00:05:23.772 --> 00:05:24.730 align:middle line:90% AUDIENCE: Part by part. 00:05:24.730 --> 00:05:26.690 align:middle line:84% MICHAEL CUTHBERT: We're going part by part. 00:05:26.690 --> 00:05:31.480 align:middle line:84% The soprano C-sharp, B, A, B, C-sharp. 00:05:31.480 --> 00:05:33.670 align:middle line:90% Fermata. 00:05:33.670 --> 00:05:36.530 align:middle line:84% It's nice to see that fermatas are not in here, 00:05:36.530 --> 00:05:38.170 align:middle line:90% so they must be someplace else. 00:05:38.170 --> 00:05:39.140 align:middle line:90% E, C-sharp. 00:05:39.140 --> 00:05:42.860 align:middle line:84% Yeah, so we're going part by part in this case. 00:05:42.860 --> 00:05:45.110 align:middle line:90% Great. 00:05:45.110 --> 00:05:48.310 align:middle line:84% And we also saw last class that we could do something. 00:05:48.310 --> 00:05:50.380 align:middle line:84% If we knew exactly where something 00:05:50.380 --> 00:05:55.200 align:middle line:84% was, we could say Bach 2, which I happen to remember, 00:05:55.200 --> 00:05:58.080 align:middle line:84% there's a metadata soprano then alto. 00:05:58.080 --> 00:05:59.998 align:middle line:90% So that would be two. 00:05:59.998 --> 00:06:00.540 align:middle line:90% I don't know. 00:06:00.540 --> 00:06:04.820 align:middle line:84% Let's choose a random measure, and we can make a list out 00:06:04.820 --> 00:06:05.400 align:middle line:90% of this. 00:06:05.400 --> 00:06:06.275 align:middle line:90% I can't remember if-- 00:06:06.275 --> 00:06:07.520 align:middle line:90% I think I demonstrated that. 00:06:07.520 --> 00:06:10.500 align:middle line:90% And get what is in here. 00:06:10.500 --> 00:06:14.270 align:middle line:84% And we'll keep seeing that these random other things keep 00:06:14.270 --> 00:06:20.240 align:middle line:84% popping up here, like system layouts and so on. 00:06:20.240 --> 00:06:26.060 align:middle line:84% So we'll need a better way to get to notes. 00:06:26.060 --> 00:06:27.150 align:middle line:90% Questions? 00:06:27.150 --> 00:06:29.010 align:middle line:84% This is review, so I went pretty fast. 00:06:29.010 --> 00:06:32.040 align:middle line:84% But the important thing is, if I'm reviewing it, 00:06:32.040 --> 00:06:34.550 align:middle line:84% it's probably important that we have good understanding 00:06:34.550 --> 00:06:36.830 align:middle line:90% before we move on. 00:06:36.830 --> 00:06:37.610 align:middle line:90% Yeah, Jake. 00:06:37.610 --> 00:06:39.150 align:middle line:84% AUDIENCE: You had us recurse on the first day? 00:06:39.150 --> 00:06:39.800 align:middle line:90% Are we going to use that? 00:06:39.800 --> 00:06:42.090 align:middle line:84% MICHAEL CUTHBERT: So we're going to get to that in just a second. 00:06:42.090 --> 00:06:42.890 align:middle line:90% Yep. 00:06:42.890 --> 00:06:43.620 align:middle line:90% Good. 00:06:43.620 --> 00:06:44.475 align:middle line:90% Yeah. 00:06:44.475 --> 00:06:45.350 align:middle line:90% AUDIENCE: Close that. 00:06:45.350 --> 00:06:46.308 align:middle line:90% MICHAEL CUTHBERT: Sure. 00:06:46.308 --> 00:06:49.070 align:middle line:90% Great, great. 00:06:49.070 --> 00:06:49.950 align:middle line:90% There we go. 00:06:49.950 --> 00:06:51.998 align:middle line:84% Sorry that the blackout blind over there 00:06:51.998 --> 00:06:53.123 align:middle line:90% doesn't seem to be working. 00:06:53.123 --> 00:06:58.010 align:middle line:90% 00:06:58.010 --> 00:06:59.480 align:middle line:84% If you email me after class, I'll 00:06:59.480 --> 00:07:01.470 align:middle line:84% remember to put in a facilities request. 00:07:01.470 --> 00:07:04.377 align:middle line:84% Or if you email me right now in class, you'll hear a ding. 00:07:04.377 --> 00:07:05.960 align:middle line:84% Then I'll put in a facilities request, 00:07:05.960 --> 00:07:09.680 align:middle line:84% because that's going to get annoying after daylight savings 00:07:09.680 --> 00:07:11.885 align:middle line:90% time starts for this class. 00:07:11.885 --> 00:07:12.385 align:middle line:90% Good. 00:07:12.385 --> 00:07:15.600 align:middle line:90% 00:07:15.600 --> 00:07:20.570 align:middle line:84% Any other things that we want before from the review 00:07:20.570 --> 00:07:21.180 align:middle line:90% last time? 00:07:21.180 --> 00:07:21.680 align:middle line:90% Yeah. 00:07:21.680 --> 00:07:23.900 align:middle line:84% I showed a whole bunch of things on the first class 00:07:23.900 --> 00:07:29.340 align:middle line:84% that are not done yet, but we'll be getting to them sooner. 00:07:29.340 --> 00:07:31.290 align:middle line:84% So assume everything on the first class, 00:07:31.290 --> 00:07:34.410 align:middle line:84% I think I said at the end, was then immediately relocked. 00:07:34.410 --> 00:07:38.750 align:middle line:84% But as far as this recurse thing, we're going to get to it 00:07:38.750 --> 00:07:42.615 align:middle line:84% and unlock it in just a few seconds. 00:07:42.615 --> 00:07:43.115 align:middle line:90% Great. 00:07:43.115 --> 00:07:46.370 align:middle line:90% 00:07:46.370 --> 00:07:51.130 align:middle line:84% So any stream can be converted to a list by doing it, 00:07:51.130 --> 00:07:53.070 align:middle line:84% so we can get the list of everything that's 00:07:53.070 --> 00:07:57.850 align:middle line:84% in the top level score for Bach here. 00:07:57.850 --> 00:08:03.070 align:middle line:84% And then we can, yeah, do other things. 00:08:03.070 --> 00:08:06.247 align:middle line:84% There are some differences between a stream and a list 00:08:06.247 --> 00:08:07.330 align:middle line:90% that are pretty important. 00:08:07.330 --> 00:08:11.560 align:middle line:84% So when I say a list, array in other languages, 00:08:11.560 --> 00:08:13.390 align:middle line:84% what are some of the things you can do? 00:08:13.390 --> 00:08:15.010 align:middle line:90% It's a mutable container. 00:08:15.010 --> 00:08:18.090 align:middle line:84% So what some things you can do to it? 00:08:18.090 --> 00:08:18.760 align:middle line:90% Yeah. 00:08:18.760 --> 00:08:19.390 align:middle line:90% AUDIENCE: You can add to it. 00:08:19.390 --> 00:08:20.470 align:middle line:84% MICHAEL CUTHBERT: You can add to it. 00:08:20.470 --> 00:08:21.180 align:middle line:90% Great. 00:08:21.180 --> 00:08:23.520 align:middle line:90% Other things? 00:08:23.520 --> 00:08:24.480 align:middle line:90% You usually can add. 00:08:24.480 --> 00:08:25.320 align:middle line:90% AUDIENCE: You can pop things. 00:08:25.320 --> 00:08:26.680 align:middle line:84% MICHAEL CUTHBERT: You can pop things off of it. 00:08:26.680 --> 00:08:27.180 align:middle line:90% Great. 00:08:27.180 --> 00:08:29.200 align:middle line:90% You can remove things out of it. 00:08:29.200 --> 00:08:31.470 align:middle line:84% What are some other things that lists do? 00:08:31.470 --> 00:08:32.340 align:middle line:90% Yeah, go ahead. 00:08:32.340 --> 00:08:34.059 align:middle line:84% AUDIENCE: You can change things at certain indices. 00:08:34.059 --> 00:08:35.799 align:middle line:84% MICHAEL CUTHBERT: You can change things at certain indices. 00:08:35.799 --> 00:08:38.150 align:middle line:84% Yeah, you can replace one thing with another. 00:08:38.150 --> 00:08:38.650 align:middle line:90% Good. 00:08:38.650 --> 00:08:42.120 align:middle line:90% Any other things we can do? 00:08:42.120 --> 00:08:42.667 align:middle line:90% Yeah, Jason. 00:08:42.667 --> 00:08:43.750 align:middle line:90% AUDIENCE: Find the length? 00:08:43.750 --> 00:08:44.920 align:middle line:84% MICHAEL CUTHBERT: You can find the length. 00:08:44.920 --> 00:08:45.450 align:middle line:90% Great. 00:08:45.450 --> 00:08:47.492 align:middle line:84% You can find the length, and you can append to it 00:08:47.492 --> 00:08:49.470 align:middle line:84% and change the length, all those things. 00:08:49.470 --> 00:08:54.010 align:middle line:84% One other thing beginning with IT that you can do. 00:08:54.010 --> 00:08:54.620 align:middle line:90% Yeah, John. 00:08:54.620 --> 00:08:55.620 align:middle line:90% AUDIENCE: Iterate on it. 00:08:55.620 --> 00:08:56.470 align:middle line:84% MICHAEL CUTHBERT: You can iterate it. 00:08:56.470 --> 00:08:58.900 align:middle line:84% You can put it into a for loop and get things. 00:08:58.900 --> 00:09:00.660 align:middle line:90% Great, great. 00:09:00.660 --> 00:09:02.208 align:middle line:90% There's one more over here. 00:09:02.208 --> 00:09:03.000 align:middle line:90% AUDIENCE: Splicing? 00:09:03.000 --> 00:09:04.375 align:middle line:84% MICHAEL CUTHBERT: Splicing, yeah. 00:09:04.375 --> 00:09:06.670 align:middle line:84% You can get little parts of it, too. 00:09:06.670 --> 00:09:14.140 align:middle line:84% So in this way a stream really does work like a list. 00:09:14.140 --> 00:09:17.260 align:middle line:84% We can get out, get rid of that metadata. 00:09:17.260 --> 00:09:20.250 align:middle line:84% We can get rid of other things here. 00:09:20.250 --> 00:09:23.590 align:middle line:84% If I had been smarter 20 years ago, 00:09:23.590 --> 00:09:26.220 align:middle line:84% it probably would inherit from list, but it does not. 00:09:26.220 --> 00:09:30.480 align:middle line:84% But it has a lot of things that are list-like. 00:09:30.480 --> 00:09:32.610 align:middle line:84% But there's some things that you can also 00:09:32.610 --> 00:09:35.790 align:middle line:90% do that are a little different. 00:09:35.790 --> 00:09:38.670 align:middle line:84% Actually, what was that over here? 00:09:38.670 --> 00:09:42.520 align:middle line:90% We went up to Bach 2, 4. 00:09:42.520 --> 00:09:44.690 align:middle line:90% Let's get that out here. 00:09:44.690 --> 00:09:49.100 align:middle line:84% I think that should be measure three. 00:09:49.100 --> 00:09:50.090 align:middle line:90% Let's see. 00:09:50.090 --> 00:09:54.080 align:middle line:84% And m equals this, and we'll see what m is. 00:09:54.080 --> 00:09:56.180 align:middle line:90% Yep, measure three. 00:09:56.180 --> 00:09:56.680 align:middle line:90% Great. 00:09:56.680 --> 00:09:59.560 align:middle line:84% So measure three of the second thing 00:09:59.560 --> 00:10:01.810 align:middle line:84% up here, so the third thing, because we're 00:10:01.810 --> 00:10:07.030 align:middle line:84% doing 2, 0 index 0, 1, 2, measure three of the alto part. 00:10:07.030 --> 00:10:09.970 align:middle line:84% Here is something that I don't think, 00:10:09.970 --> 00:10:13.160 align:middle line:84% for all the amazing things MIT CS training does, 00:10:13.160 --> 00:10:15.230 align:middle line:84% I don't think it does very, very well. 00:10:15.230 --> 00:10:19.310 align:middle line:84% I think that this says measure three of the alto part. 00:10:19.310 --> 00:10:20.870 align:middle line:90% And here's the contents of it. 00:10:20.870 --> 00:10:22.790 align:middle line:84% Let's just go through and make sure. 00:10:22.790 --> 00:10:24.945 align:middle line:84% Remember, pickups are measure what? 00:10:24.945 --> 00:10:25.570 align:middle line:90% AUDIENCE: Zero. 00:10:25.570 --> 00:10:26.095 align:middle line:90% MICHAEL CUTHBERT: Zero. 00:10:26.095 --> 00:10:28.615 align:middle line:84% So let's make sure that this is actually measure three. 00:10:28.615 --> 00:10:32.500 align:middle line:90% 00:10:32.500 --> 00:10:33.200 align:middle line:90% Is that right? 00:10:33.200 --> 00:10:34.980 align:middle line:90% Do we get the right measure? 00:10:34.980 --> 00:10:39.520 align:middle line:90% 00:10:39.520 --> 00:10:41.195 align:middle line:84% The next problem set, the one that we're 00:10:41.195 --> 00:10:43.070 align:middle line:84% going to be talking about at the end of class 00:10:43.070 --> 00:10:47.720 align:middle line:84% today, it's probably the least time 00:10:47.720 --> 00:10:52.200 align:middle line:84% consuming of any of the ones you've had so far, so good. 00:10:52.200 --> 00:10:54.900 align:middle line:84% I figure every third one, you need a little bit of a break. 00:10:54.900 --> 00:10:56.430 align:middle line:90% So we'll go down on that. 00:10:56.430 --> 00:10:59.180 align:middle line:84% I will tell you in advance where people 00:10:59.180 --> 00:11:04.020 align:middle line:84% lose points on this problem set, is that they write the code, 00:11:04.020 --> 00:11:05.940 align:middle line:84% the code works, and then they go on, 00:11:05.940 --> 00:11:07.940 align:middle line:84% and there's a little programming error somewhere 00:11:07.940 --> 00:11:11.240 align:middle line:84% that could have easily been fixed by looking at the score 00:11:11.240 --> 00:11:15.560 align:middle line:84% during show and checking that your answer was actually 00:11:15.560 --> 00:11:17.160 align:middle line:90% what it should be. 00:11:17.160 --> 00:11:22.060 align:middle line:84% So just to have that there, and that's now, 00:11:22.060 --> 00:11:25.050 align:middle line:84% my feeling is everybody can get an A plus. 00:11:25.050 --> 00:11:27.480 align:middle line:84% We can all get perfects on everything. 00:11:27.480 --> 00:11:32.810 align:middle line:84% I don't need to play gotcha games for [LAUGH]. 00:11:32.810 --> 00:11:34.950 align:middle line:90% Now there's nothing to mark off. 00:11:34.950 --> 00:11:35.460 align:middle line:90% So good. 00:11:35.460 --> 00:11:37.290 align:middle line:84% So make sure that you're always doing that, 00:11:37.290 --> 00:11:40.010 align:middle line:84% and make sure to do these column sanity checks, 00:11:40.010 --> 00:11:41.720 align:middle line:84% that you're getting out from your data 00:11:41.720 --> 00:11:44.090 align:middle line:90% what you should be getting in. 00:11:44.090 --> 00:11:47.510 align:middle line:84% OK, so these are some things that are similar. 00:11:47.510 --> 00:11:51.930 align:middle line:90% One of the things, though, in-- 00:11:51.930 --> 00:11:54.210 align:middle line:84% so we have this measure, object n. 00:11:54.210 --> 00:11:54.710 align:middle line:90% We'll look. 00:11:54.710 --> 00:11:57.212 align:middle line:90% 00:11:57.212 --> 00:12:00.020 align:middle line:84% Shape of your brackets does matter. 00:12:00.020 --> 00:12:01.560 align:middle line:90% You have something here. 00:12:01.560 --> 00:12:09.080 align:middle line:84% Now, if this was just a normal list, m dot insert 2, 00:12:09.080 --> 00:12:11.250 align:middle line:84% we're going to put it position 2. 00:12:11.250 --> 00:12:12.680 align:middle line:90% Let's put a note dot note. 00:12:12.680 --> 00:12:14.270 align:middle line:84% Let's do one that we can immediately 00:12:14.270 --> 00:12:18.480 align:middle line:90% recognize, A double flat 4. 00:12:18.480 --> 00:12:20.760 align:middle line:90% We can create an object in here. 00:12:20.760 --> 00:12:22.950 align:middle line:90% Actually, we'll be smart. 00:12:22.950 --> 00:12:27.350 align:middle line:84% We'll call that n and define it before n equals, 00:12:27.350 --> 00:12:29.490 align:middle line:84% so that we can reference it again. 00:12:29.490 --> 00:12:32.660 align:middle line:84% Sorry, I'll try not to get this at the very bottom 00:12:32.660 --> 00:12:33.260 align:middle line:90% of the screen. 00:12:33.260 --> 00:12:33.760 align:middle line:90% Great. 00:12:33.760 --> 00:12:44.040 align:middle line:90% 00:12:44.040 --> 00:12:51.440 align:middle line:84% So what should have happened if this were a normal list? 00:12:51.440 --> 00:12:56.280 align:middle line:84% Where would you have expected to see that double flat, 00:12:56.280 --> 00:12:59.060 align:middle line:90% A double flat? 00:12:59.060 --> 00:12:59.600 align:middle line:90% Adam. 00:12:59.600 --> 00:13:00.660 align:middle line:90% AUDIENCE: After the G-sharp. 00:13:00.660 --> 00:13:02.160 align:middle line:84% MICHAEL CUTHBERT: After the G-sharp. 00:13:02.160 --> 00:13:04.190 align:middle line:90% 00:13:04.190 --> 00:13:05.930 align:middle line:90% Everybody agree? 00:13:05.930 --> 00:13:09.050 align:middle line:84% Sometimes everybody agrees when the professor's like, yeah, does 00:13:09.050 --> 00:13:10.590 align:middle line:90% it go after two or does it-- 00:13:10.590 --> 00:13:13.170 align:middle line:84% I can't remember, but yeah, I'm pretty sure that's right. 00:13:13.170 --> 00:13:17.780 align:middle line:84% So it should be somewhere over here. 00:13:17.780 --> 00:13:18.900 align:middle line:90% Why is it here? 00:13:18.900 --> 00:13:23.390 align:middle line:84% Let's go back to that alto part, measure 2, 00:13:23.390 --> 00:13:27.410 align:middle line:84% and see it's coming after the C-sharp. 00:13:27.410 --> 00:13:30.652 align:middle line:84% Does the C-sharp have a fermata on it or not? 00:13:30.652 --> 00:13:32.860 align:middle line:84% I just want to make sure we're all on the same place. 00:13:32.860 --> 00:13:39.300 align:middle line:90% 00:13:39.300 --> 00:13:42.720 align:middle line:84% Yeah, John's nodding his head and John's almost always 00:13:42.720 --> 00:13:46.230 align:middle line:84% right on these things, so good, good. 00:13:46.230 --> 00:13:49.550 align:middle line:84% And yeah, so we have it on the last "ya" 00:13:49.550 --> 00:13:53.284 align:middle line:84% of that word that I'm not going to say during Lent, right? 00:13:53.284 --> 00:13:54.820 align:middle line:90% And good. 00:13:54.820 --> 00:13:56.740 align:middle line:84% So it's come in right after there, 00:13:56.740 --> 00:14:01.680 align:middle line:84% and yet we said we should put it at 2. 00:14:01.680 --> 00:14:05.400 align:middle line:90% What might be happening here? 00:14:05.400 --> 00:14:06.420 align:middle line:90% Yeah, John. 00:14:06.420 --> 00:14:10.980 align:middle line:84% AUDIENCE: It's being put at the second beat, 12, 0 index. 00:14:10.980 --> 00:14:14.070 align:middle line:84% MICHAEL CUTHBERT: The second beat, yeah, 00:14:14.070 --> 00:14:16.510 align:middle line:90% with the beginning being 0. 00:14:16.510 --> 00:14:19.570 align:middle line:84% Now, I told you that's very, very close to the right answer. 00:14:19.570 --> 00:14:20.915 align:middle line:90% So great, great. 00:14:20.915 --> 00:14:22.290 align:middle line:84% I said at the beginning there was 00:14:22.290 --> 00:14:26.140 align:middle line:84% a reason why I didn't like to use beat as a fundamental unit. 00:14:26.140 --> 00:14:27.185 align:middle line:90% What was that? 00:14:27.185 --> 00:14:30.480 align:middle line:90% 00:14:30.480 --> 00:14:35.250 align:middle line:84% Or because of things like 5/8 where the-- 00:14:35.250 --> 00:14:41.190 align:middle line:84% fast 5/8, 1, 1 and 2, and a 1 and 2 and a, where beats can 00:14:41.190 --> 00:14:44.830 align:middle line:84% change their duration even within a measure. 00:14:44.830 --> 00:14:48.610 align:middle line:90% So what's something equivalent? 00:14:48.610 --> 00:14:51.037 align:middle line:84% What would durations measured in? 00:14:51.037 --> 00:14:52.620 align:middle line:84% I'm going to call on Misha next, but I 00:14:52.620 --> 00:14:54.420 align:middle line:84% want to make sure that we have-- yeah, Misha. 00:14:54.420 --> 00:14:55.560 align:middle line:84% AUDIENCE: Yeah, I think it was just said. 00:14:55.560 --> 00:14:57.990 align:middle line:84% I think you said you used quarter notes, I assume. 00:14:57.990 --> 00:14:59.740 align:middle line:84% MICHAEL CUTHBERT: Yeah, so quarter length. 00:14:59.740 --> 00:15:01.960 align:middle line:84% So in this case, it's exactly the same as beat. 00:15:01.960 --> 00:15:04.530 align:middle line:84% So this correct answer in this case, 00:15:04.530 --> 00:15:06.196 align:middle line:90% because we're in four quarters. 00:15:06.196 --> 00:15:09.450 align:middle line:90% But so we've put it in-- 00:15:09.450 --> 00:15:10.210 align:middle line:90% what do we have? 00:15:10.210 --> 00:15:11.110 align:middle line:90% Eighth, eighth. 00:15:11.110 --> 00:15:18.750 align:middle line:84% So that's all within 0, 0.5, 1, 2. 00:15:18.750 --> 00:15:21.670 align:middle line:84% But there might be a problem here. 00:15:21.670 --> 00:15:26.070 align:middle line:90% Why is it after the C-sharp? 00:15:26.070 --> 00:15:27.970 align:middle line:90% Well, let's do this. 00:15:27.970 --> 00:15:30.210 align:middle line:84% We remember some of our iteration 00:15:30.210 --> 00:15:33.750 align:middle line:84% for, I'll still, say thing in m, even though they're mostly 00:15:33.750 --> 00:15:34.510 align:middle line:90% notes. 00:15:34.510 --> 00:15:38.480 align:middle line:90% Print thing and things. 00:15:38.480 --> 00:15:42.640 align:middle line:84% New term that we haven't seen, it's offset. 00:15:42.640 --> 00:15:45.880 align:middle line:84% So the offset, just like the duration 00:15:45.880 --> 00:15:48.250 align:middle line:84% is measured in quarter lengths, the offset 00:15:48.250 --> 00:15:51.610 align:middle line:84% from the beginning of the current container 00:15:51.610 --> 00:15:53.930 align:middle line:90% is measured in quarter lengths. 00:15:53.930 --> 00:15:55.730 align:middle line:90% So we have here. 00:15:55.730 --> 00:15:59.690 align:middle line:84% And we can actually now have two notes at the same time. 00:15:59.690 --> 00:16:03.800 align:middle line:84% So you can have multiple things at the same position. 00:16:03.800 --> 00:16:05.380 align:middle line:84% That makes it a little bit harder 00:16:05.380 --> 00:16:10.400 align:middle line:84% to remove by offset that you want to have, 00:16:10.400 --> 00:16:13.870 align:middle line:84% because unlike in an array where there can only 00:16:13.870 --> 00:16:16.510 align:middle line:84% be one thing at a particular index, here 00:16:16.510 --> 00:16:20.350 align:middle line:84% you can have multiple things at the same index. 00:16:20.350 --> 00:16:22.040 align:middle line:90% This is a simplification. 00:16:22.040 --> 00:16:25.420 align:middle line:84% We'll see in a little bit that notes and everything else 00:16:25.420 --> 00:16:29.060 align:middle line:84% can have an infinite number of offsets simultaneously. 00:16:29.060 --> 00:16:33.940 align:middle line:84% But this is good enough to start here. 00:16:33.940 --> 00:16:35.350 align:middle line:90% Yeah, go ahead. 00:16:35.350 --> 00:16:37.720 align:middle line:84% AUDIENCE: So if you do show, it doesn't put them 00:16:37.720 --> 00:16:38.650 align:middle line:90% in the same place. 00:16:38.650 --> 00:16:40.817 align:middle line:84% MICHAEL CUTHBERT: If you put it in show, it doesn't. 00:16:40.817 --> 00:16:43.720 align:middle line:84% Right, because not, that's a great thing. 00:16:43.720 --> 00:16:47.770 align:middle line:84% You're going to find it is easy to create things that are valid 00:16:47.770 --> 00:16:56.230 align:middle line:84% musical concepts that cannot be shown by any of our music 00:16:56.230 --> 00:16:59.410 align:middle line:84% representation software, our MuseScores, or Finales, 00:16:59.410 --> 00:17:01.360 align:middle line:90% or whatever like that. 00:17:01.360 --> 00:17:01.960 align:middle line:90% Why? 00:17:01.960 --> 00:17:06.280 align:middle line:84% Because if you have a part, do you have two-- 00:17:06.280 --> 00:17:08.599 align:middle line:90% This is an ontological question. 00:17:08.599 --> 00:17:12.780 align:middle line:84% Do you have two notes that sound at the same time in one part? 00:17:12.780 --> 00:17:15.550 align:middle line:90% 00:17:15.550 --> 00:17:18.250 align:middle line:84% Or do you have something else that 00:17:18.250 --> 00:17:23.200 align:middle line:84% happens when you have two notes at the same time? 00:17:23.200 --> 00:17:26.589 align:middle line:84% What other representation might be for two notes, 00:17:26.589 --> 00:17:29.360 align:middle line:84% for two things that sound at the same time? 00:17:29.360 --> 00:17:30.150 align:middle line:90% I won't say notes. 00:17:30.150 --> 00:17:33.770 align:middle line:90% 00:17:33.770 --> 00:17:35.867 align:middle line:90% Nobody? 00:17:35.867 --> 00:17:36.950 align:middle line:90% AUDIENCE: Different parts? 00:17:36.950 --> 00:17:38.390 align:middle line:84% MICHAEL CUTHBERT: You would have-- 00:17:38.390 --> 00:17:40.340 align:middle line:84% A, you could have it in two different parts, which 00:17:40.340 --> 00:17:41.180 align:middle line:90% is what we've normally seen. 00:17:41.180 --> 00:17:41.750 align:middle line:90% Or yep. 00:17:41.750 --> 00:17:44.780 align:middle line:84% AUDIENCE: You can have a split, like one person going 00:17:44.780 --> 00:17:45.420 align:middle line:90% up and down. 00:17:45.420 --> 00:17:47.295 align:middle line:84% MICHAEL CUTHBERT: Yeah, you can have a split. 00:17:47.295 --> 00:17:48.120 align:middle line:90% Yeah, a split. 00:17:48.120 --> 00:17:50.028 align:middle line:90% We call those voices in this. 00:17:50.028 --> 00:17:51.570 align:middle line:84% So you have two voices at that thing. 00:17:51.570 --> 00:17:56.090 align:middle line:84% What's the other thing, another fundamental part 00:17:56.090 --> 00:17:57.590 align:middle line:90% of our ontologies? 00:17:57.590 --> 00:17:58.183 align:middle line:90% [PIANO CHORD] 00:17:58.183 --> 00:17:58.850 align:middle line:90% AUDIENCE: Chord? 00:17:58.850 --> 00:17:59.850 align:middle line:90% MICHAEL CUTHBERT: Chord. 00:17:59.850 --> 00:18:03.020 align:middle line:84% So in this case, your software wants 00:18:03.020 --> 00:18:05.630 align:middle line:84% me to have created a chord object, which is not yet 00:18:05.630 --> 00:18:07.920 align:middle line:84% unlocked for us out of these two. 00:18:07.920 --> 00:18:11.490 align:middle line:84% So it just does whatever it wants with it. 00:18:11.490 --> 00:18:12.830 align:middle line:90% Great question. 00:18:12.830 --> 00:18:13.430 align:middle line:90% Super. 00:18:13.430 --> 00:18:15.240 align:middle line:90% So keep playing with the limits. 00:18:15.240 --> 00:18:17.030 align:middle line:84% We're a little bit behind in time 00:18:17.030 --> 00:18:20.880 align:middle line:84% because we're really asking great questions. 00:18:20.880 --> 00:18:23.900 align:middle line:84% So I'm going to hold off a little bit on some 00:18:23.900 --> 00:18:29.550 align:middle line:84% until we can get a little bit further into some things. 00:18:29.550 --> 00:18:33.750 align:middle line:90% So yeah, question. 00:18:33.750 --> 00:18:34.290 align:middle line:90% Go ahead. 00:18:34.290 --> 00:18:35.580 align:middle line:90% AUDIENCE: How do you remove? 00:18:35.580 --> 00:18:37.080 align:middle line:84% MICHAEL CUTHBERT: How do you remove? 00:18:37.080 --> 00:18:41.930 align:middle line:84% Well, you'll be able to-- you can either remove the thing, 00:18:41.930 --> 00:18:45.500 align:middle line:84% and it will find it, Or you can remove something at an offset. 00:18:45.500 --> 00:18:49.790 align:middle line:84% And fortunately, all of these other things 00:18:49.790 --> 00:18:52.460 align:middle line:84% will be-- all these other options 00:18:52.460 --> 00:18:57.260 align:middle line:84% will be revealed to you in the reading 00:18:57.260 --> 00:19:00.110 align:middle line:84% before next time we meet together, 00:19:00.110 --> 00:19:03.900 align:middle line:84% which is the user's guide chapter on streams. 00:19:03.900 --> 00:19:06.660 align:middle line:84% So I think that remove is mentioned in there. 00:19:06.660 --> 00:19:08.850 align:middle line:84% It can be a little bit more complicated, as I said, 00:19:08.850 --> 00:19:15.530 align:middle line:84% so I want to hold that off for just a little bit. 00:19:15.530 --> 00:19:19.530 align:middle line:84% Let me do another little thing for a second, 00:19:19.530 --> 00:19:24.620 align:middle line:84% and we'll jump to some ways that we can make our life easier 00:19:24.620 --> 00:19:26.480 align:middle line:84% by not doing for thing and thing, 00:19:26.480 --> 00:19:28.650 align:middle line:84% than for next thing and thing, next thing in fixing 00:19:28.650 --> 00:19:30.210 align:middle line:90% the previous thing. 00:19:30.210 --> 00:19:35.440 align:middle line:84% Obviously, we're going to have some other ideas. 00:19:35.440 --> 00:19:40.410 align:middle line:84% So this is one notion, one way a score might be represented 00:19:40.410 --> 00:19:43.560 align:middle line:90% in Music21 with two parts. 00:19:43.560 --> 00:19:50.370 align:middle line:84% And so within the score in this, its score's length is how much? 00:19:50.370 --> 00:19:51.227 align:middle line:90% Just shout it out. 00:19:51.227 --> 00:19:51.810 align:middle line:90% AUDIENCE: Two. 00:19:51.810 --> 00:19:52.800 align:middle line:90% AUDIENCE: Two. 00:19:52.800 --> 00:19:54.160 align:middle line:90% MICHAEL CUTHBERT: Two or? 00:19:54.160 --> 00:19:54.500 align:middle line:90% AUDIENCE: Three. 00:19:54.500 --> 00:19:56.792 align:middle line:84% MICHAEL CUTHBERT: Three, because we have this metadata. 00:19:56.792 --> 00:19:59.170 align:middle line:84% And so I've put underneath is the offset of everything. 00:19:59.170 --> 00:20:03.670 align:middle line:84% Both parts start at the beginning of the score. 00:20:03.670 --> 00:20:05.260 align:middle line:90% So they have offset 0. 00:20:05.260 --> 00:20:08.850 align:middle line:84% Within part one, there are two, I'm calling, 00:20:08.850 --> 00:20:13.560 align:middle line:90% measures measure 1a, measure 2a. 00:20:13.560 --> 00:20:17.880 align:middle line:84% Their offsets are at 0 and 4, which makes sense 00:20:17.880 --> 00:20:22.405 align:middle line:84% because somewhere in here, there's a 4/4 time signature. 00:20:22.405 --> 00:20:26.130 align:middle line:90% 00:20:26.130 --> 00:20:29.080 align:middle line:84% Notice, though, that when we're looking at measure two, 00:20:29.080 --> 00:20:34.660 align:middle line:84% measure two's offset is 4, but we start again with offset 0. 00:20:34.660 --> 00:20:39.000 align:middle line:84% So if you want to know how many quarter notes into the piece 00:20:39.000 --> 00:20:47.970 align:middle line:84% quarter note 9 happens, you'd have to add 2 plus 4 plus 0. 00:20:47.970 --> 00:20:50.550 align:middle line:84% Fortunately, adding 0 is easy, so you get, ah, 00:20:50.550 --> 00:20:52.810 align:middle line:84% it's 6 quarter notes into the piece. 00:20:52.810 --> 00:20:57.450 align:middle line:84% So this is one, the representation that's happening. 00:20:57.450 --> 00:21:01.650 align:middle line:84% Now, when you iterate over the score for all size-- use el, 00:21:01.650 --> 00:21:02.925 align:middle line:90% element-- 00:21:02.925 --> 00:21:05.680 align:middle line:84% thing, things comes off the tongue better, 00:21:05.680 --> 00:21:07.420 align:middle line:90% but el is quicker to type. 00:21:07.420 --> 00:21:12.180 align:middle line:84% And when you do this, you'll see that-- we've already 00:21:12.180 --> 00:21:16.740 align:middle line:84% seen you get the metadata, you get part one, 00:21:16.740 --> 00:21:20.710 align:middle line:84% and then you get part two, and that's all. 00:21:20.710 --> 00:21:24.000 align:middle line:84% So you get the three things that are there. 00:21:24.000 --> 00:21:26.890 align:middle line:84% The more powerful way to do this is something 00:21:26.890 --> 00:21:31.190 align:middle line:84% called recurse, the recurse method on here. 00:21:31.190 --> 00:21:35.840 align:middle line:84% And what this does is it goes through the first thing, 00:21:35.840 --> 00:21:38.300 align:middle line:84% and then if there's anything inside the metadata, 00:21:38.300 --> 00:21:41.330 align:middle line:84% which there isn't-- it's not a container-- it would go into it. 00:21:41.330 --> 00:21:44.680 align:middle line:84% Then part one is a container class. 00:21:44.680 --> 00:21:46.490 align:middle line:84% All containers are called streams, 00:21:46.490 --> 00:21:49.630 align:middle line:84% but the general term in computational music theory 00:21:49.630 --> 00:21:51.260 align:middle line:90% is the container. 00:21:51.260 --> 00:21:55.430 align:middle line:84% And then within this container, we have another container, 00:21:55.430 --> 00:21:58.700 align:middle line:84% and it will go through these things that are not containers. 00:21:58.700 --> 00:22:02.230 align:middle line:84% Sometimes these are called leaves, the leaf node, 00:22:02.230 --> 00:22:05.600 align:middle line:84% like in a graph, the thing that has no descendants on it. 00:22:05.600 --> 00:22:07.840 align:middle line:84% And then it will go through the second one. 00:22:07.840 --> 00:22:12.070 align:middle line:84% Then it jumps back to part two and goes through each one, 00:22:12.070 --> 00:22:13.160 align:middle line:90% and tells you that. 00:22:13.160 --> 00:22:16.580 align:middle line:84% So that's going to make life a lot easier. 00:22:16.580 --> 00:22:18.323 align:middle line:90% Let's recurse through. 00:22:18.323 --> 00:22:21.370 align:middle line:90% 00:22:21.370 --> 00:22:23.170 align:middle line:90% Can I move over here? 00:22:23.170 --> 00:22:26.620 align:middle line:90% Let's recurse through Bach. 00:22:26.620 --> 00:22:31.940 align:middle line:84% For el in Bach dot recurse, print. 00:22:31.940 --> 00:22:33.856 align:middle line:90% Let's do el and el's offset. 00:22:33.856 --> 00:22:38.010 align:middle line:90% 00:22:38.010 --> 00:22:38.510 align:middle line:90% Oops. 00:22:38.510 --> 00:22:41.560 align:middle line:84% And now I have to get my scrolling back. 00:22:41.560 --> 00:22:44.050 align:middle line:90% Here we go. 00:22:44.050 --> 00:22:46.820 align:middle line:84% So now, we're seeing there's the metadata. 00:22:46.820 --> 00:22:48.320 align:middle line:90% There's the soprano part. 00:22:48.320 --> 00:22:53.050 align:middle line:84% If we were writing a program, we could keep track of what part 00:22:53.050 --> 00:22:55.970 align:middle line:84% we're in at a certain point, and every time we see a new part, 00:22:55.970 --> 00:22:56.710 align:middle line:90% do something. 00:22:56.710 --> 00:22:59.030 align:middle line:84% And then we see, oh, we're at measures zero. 00:22:59.030 --> 00:22:59.870 align:middle line:90% Here we go. 00:22:59.870 --> 00:23:04.730 align:middle line:84% Here's all the different things to measure one, measure two. 00:23:04.730 --> 00:23:09.520 align:middle line:84% And if I scroll far enough, eventually, we should see-- 00:23:09.520 --> 00:23:13.270 align:middle line:90% here we go-- part alto. 00:23:13.270 --> 00:23:17.140 align:middle line:90% So that's pretty good. 00:23:17.140 --> 00:23:19.210 align:middle line:84% All this information about what's 00:23:19.210 --> 00:23:22.670 align:middle line:84% its offset and things, this can be done, 00:23:22.670 --> 00:23:25.790 align:middle line:84% also gotten in a way that just prints. 00:23:25.790 --> 00:23:27.560 align:middle line:90% It's not useful for parsing. 00:23:27.560 --> 00:23:28.940 align:middle line:90% I would not say parse this. 00:23:28.940 --> 00:23:35.950 align:middle line:84% But if you do Bach dot show text, and it just gives you, 00:23:35.950 --> 00:23:40.990 align:middle line:84% basically, the same information as that routine, but nicely 00:23:40.990 --> 00:23:43.420 align:middle line:90% formatted. 00:23:43.420 --> 00:23:49.220 align:middle line:84% So I'll give a second where the current offset is given first, 00:23:49.220 --> 00:23:56.140 align:middle line:84% and then the next thing also puts everything like this. 00:23:56.140 --> 00:24:00.800 align:middle line:90% Questions on this part? 00:24:00.800 --> 00:24:03.820 align:middle line:84% Now your computer science question. 00:24:03.820 --> 00:24:08.900 align:middle line:84% Recurse is what type of graph search? 00:24:08.900 --> 00:24:10.130 align:middle line:90% Don't shout it out yet. 00:24:10.130 --> 00:24:11.180 align:middle line:90% We'll let everyone think. 00:24:11.180 --> 00:24:15.460 align:middle line:84% There are a number of ways of searching through a graph 00:24:15.460 --> 00:24:17.000 align:middle line:90% or iterating through a graph. 00:24:17.000 --> 00:24:21.560 align:middle line:90% What kind would we call this? 00:24:21.560 --> 00:24:22.440 align:middle line:90% I'll give you a hint. 00:24:22.440 --> 00:24:26.790 align:middle line:84% The second word is usually first. 00:24:26.790 --> 00:24:28.110 align:middle line:90% That wasn't much of a hint. 00:24:28.110 --> 00:24:32.990 align:middle line:84% So raise your hand if you're confident that the answer 00:24:32.990 --> 00:24:38.330 align:middle line:84% to this now, and go like this if you're not confident 00:24:38.330 --> 00:24:39.930 align:middle line:90% that you know the answer. 00:24:39.930 --> 00:24:40.430 align:middle line:90% Great. 00:24:40.430 --> 00:24:42.960 align:middle line:84% Could you talk with the person next to you, 00:24:42.960 --> 00:24:45.290 align:middle line:84% and especially if you have a couple people who 00:24:45.290 --> 00:24:47.840 align:middle line:84% aren't so confident, and share your answer 00:24:47.840 --> 00:24:50.335 align:middle line:84% and see if you're in the same boat? 00:24:50.335 --> 00:24:53.030 align:middle line:90% 00:24:53.030 --> 00:24:57.620 align:middle line:84% Who is now a little bit less-- is still unconfident? 00:24:57.620 --> 00:25:00.920 align:middle line:84% Who didn't come to an agreement on your thing? 00:25:00.920 --> 00:25:03.560 align:middle line:84% You guys are still in disagreement. 00:25:03.560 --> 00:25:04.830 align:middle line:90% No, you're in agreement. 00:25:04.830 --> 00:25:06.210 align:middle line:90% Good, good. 00:25:06.210 --> 00:25:09.860 align:middle line:90% So let's all shout it out. 00:25:09.860 --> 00:25:11.930 align:middle line:90% The kind of search is a-- 00:25:11.930 --> 00:25:12.740 align:middle line:90% AUDIENCE: Depth. 00:25:12.740 --> 00:25:14.970 align:middle line:84% MICHAEL CUTHBERT: First search, a depth first search. 00:25:14.970 --> 00:25:15.470 align:middle line:90% Good. 00:25:15.470 --> 00:25:19.680 align:middle line:84% So we're always going to be following the leftmost-- 00:25:19.680 --> 00:25:23.960 align:middle line:84% I should do this in different colors so it's easier to see. 00:25:23.960 --> 00:25:28.250 align:middle line:84% The leftmost node that we haven't yet seen, 00:25:28.250 --> 00:25:32.010 align:middle line:84% and doing something with that, and then going back up, here, 00:25:32.010 --> 00:25:34.260 align:middle line:90% going back up, down. 00:25:34.260 --> 00:25:38.990 align:middle line:84% Does that seem to fit other people's computer science 00:25:38.990 --> 00:25:39.690 align:middle line:90% things? 00:25:39.690 --> 00:25:42.950 align:middle line:84% I have neither a concentration minor, major, 00:25:42.950 --> 00:25:44.760 align:middle line:90% or PhD in computer science. 00:25:44.760 --> 00:25:46.513 align:middle line:84% So please, if I get something wrong, 00:25:46.513 --> 00:25:48.680 align:middle line:84% you all shout to me because you've done more of that 00:25:48.680 --> 00:25:50.830 align:middle line:90% than I have. 00:25:50.830 --> 00:25:51.330 align:middle line:90% Great. 00:25:51.330 --> 00:25:52.890 align:middle line:90% So we have depth first search. 00:25:52.890 --> 00:25:55.790 align:middle line:84% What are some of the things anybody knows from other things 00:25:55.790 --> 00:25:58.170 align:middle line:84% that depth first searches are good for? 00:25:58.170 --> 00:26:01.880 align:middle line:84% And what are some of the things that they're not good at? 00:26:01.880 --> 00:26:04.885 align:middle line:84% So good for anybody who wants to say. 00:26:04.885 --> 00:26:08.950 align:middle line:90% 00:26:08.950 --> 00:26:09.450 align:middle line:90% Don't worry. 00:26:09.450 --> 00:26:13.637 align:middle line:90% It's a safe space. 00:26:13.637 --> 00:26:14.970 align:middle line:90% AUDIENCE: Shortest path problem? 00:26:14.970 --> 00:26:16.637 align:middle line:84% MICHAEL CUTHBERT: Shortest path problem. 00:26:16.637 --> 00:26:17.333 align:middle line:90% Good. 00:26:17.333 --> 00:26:18.250 align:middle line:90% Shortest path problem. 00:26:18.250 --> 00:26:19.710 align:middle line:90% Anybody, do you want to explain? 00:26:19.710 --> 00:26:22.170 align:middle line:84% Or anybody else want to explain what that is for those who 00:26:22.170 --> 00:26:22.670 align:middle line:90% haven't? 00:26:22.670 --> 00:26:25.110 align:middle line:90% 00:26:25.110 --> 00:26:28.480 align:middle line:84% Shortest path between two nodes, how to get there. 00:26:28.480 --> 00:26:29.780 align:middle line:90% You might not want to do. 00:26:29.780 --> 00:26:31.280 align:middle line:84% Something else it might be good for? 00:26:31.280 --> 00:26:35.730 align:middle line:90% 00:26:35.730 --> 00:26:36.240 align:middle line:90% Yeah. 00:26:36.240 --> 00:26:38.365 align:middle line:84% AUDIENCE: It's just when you're in a scenario where 00:26:38.365 --> 00:26:41.840 align:middle line:84% you think you want to look over every possible object. 00:26:41.840 --> 00:26:42.840 align:middle line:90% MICHAEL CUTHBERT: Great. 00:26:42.840 --> 00:26:46.240 align:middle line:84% In a scenario where you want to look at every possible object. 00:26:46.240 --> 00:26:48.450 align:middle line:84% Now, there's other search methods 00:26:48.450 --> 00:26:54.340 align:middle line:84% that also have that property, but this one has that property. 00:26:54.340 --> 00:26:57.030 align:middle line:84% So it's already a lot better than for thing and thing 00:26:57.030 --> 00:26:58.620 align:middle line:84% than thing and thing, thing and thing. 00:26:58.620 --> 00:27:01.300 align:middle line:84% You know that you're going to get to every point. 00:27:01.300 --> 00:27:04.731 align:middle line:84% What's something that it might not be good for, 00:27:04.731 --> 00:27:06.660 align:middle line:84% or that another search method might 00:27:06.660 --> 00:27:08.255 align:middle line:90% be a better way of doing it? 00:27:08.255 --> 00:27:12.870 align:middle line:90% 00:27:12.870 --> 00:27:13.423 align:middle line:90% Yeah. 00:27:13.423 --> 00:27:15.840 align:middle line:84% AUDIENCE: In the case of breadth first search versus depth 00:27:15.840 --> 00:27:18.480 align:middle line:84% first search, if something's close by, 00:27:18.480 --> 00:27:19.740 align:middle line:90% there's not a lot of it. 00:27:19.740 --> 00:27:23.370 align:middle line:90% Or the tree is super deep. 00:27:23.370 --> 00:27:25.273 align:middle line:90% But the answer is super close. 00:27:25.273 --> 00:27:26.190 align:middle line:90% MICHAEL CUTHBERT: Yep. 00:27:26.190 --> 00:27:28.648 align:middle line:84% AUDIENCE: Depth first search will search through every one. 00:27:28.648 --> 00:27:30.270 align:middle line:84% Or to go to the depths of the tree. 00:27:30.270 --> 00:27:30.900 align:middle line:90% MICHAEL CUTHBERT: The tree. 00:27:30.900 --> 00:27:32.310 align:middle line:84% AUDIENCE: Just to check in the first couple. 00:27:32.310 --> 00:27:33.310 align:middle line:90% MICHAEL CUTHBERT: Great. 00:27:33.310 --> 00:27:33.880 align:middle line:90% Super, super. 00:27:33.880 --> 00:27:36.340 align:middle line:84% And we should say what we're comparing. 00:27:36.340 --> 00:27:37.840 align:middle line:84% There's lots and lots of searches, 00:27:37.840 --> 00:27:41.200 align:middle line:84% but the two key ones, we have depth first search, 00:27:41.200 --> 00:27:42.630 align:middle line:90% and it's compared to what? 00:27:42.630 --> 00:27:43.380 align:middle line:90% AUDIENCE: Breadth. 00:27:43.380 --> 00:27:45.005 align:middle line:84% MICHAEL CUTHBERT: Breadth first search. 00:27:45.005 --> 00:27:46.990 align:middle line:84% Yep, the breakfast search as I always say. 00:27:46.990 --> 00:27:48.820 align:middle line:90% Breadth first search. 00:27:48.820 --> 00:27:51.390 align:middle line:84% So that one, what are we going to do 00:27:51.390 --> 00:27:53.920 align:middle line:84% if we want to breadth first search in here? 00:27:53.920 --> 00:27:56.490 align:middle line:90% What are we going to see first? 00:27:56.490 --> 00:27:58.600 align:middle line:84% What's the first node we're going to visit? 00:27:58.600 --> 00:27:59.220 align:middle line:90% AUDIENCE: SC. 00:27:59.220 --> 00:28:00.790 align:middle line:90% MICHAEL CUTHBERT: SC, the score. 00:28:00.790 --> 00:28:01.290 align:middle line:90% Good. 00:28:01.290 --> 00:28:03.790 align:middle line:84% So, so far, it's exactly the same as the depth first search. 00:28:03.790 --> 00:28:05.840 align:middle line:84% Second node we're going to see in this side? 00:28:05.840 --> 00:28:06.660 align:middle line:90% AUDIENCE: Part one. 00:28:06.660 --> 00:28:08.035 align:middle line:84% MICHAEL CUTHBERT: Part one, good. 00:28:08.035 --> 00:28:08.550 align:middle line:90% Third node? 00:28:08.550 --> 00:28:09.150 align:middle line:90% AUDIENCE: Part two. 00:28:09.150 --> 00:28:10.275 align:middle line:90% MICHAEL CUTHBERT: Part two. 00:28:10.275 --> 00:28:11.430 align:middle line:90% So we're already different. 00:28:11.430 --> 00:28:12.630 align:middle line:90% Next node? 00:28:12.630 --> 00:28:13.540 align:middle line:90% [INTERPOSING VOICES] 00:28:13.540 --> 00:28:14.030 align:middle line:90% MICHAEL CUTHBERT: Was one. 00:28:14.030 --> 00:28:14.530 align:middle line:90% Yep. 00:28:14.530 --> 00:28:17.020 align:middle line:84% AUDIENCE: For one, isn't BFS better for shortest path 00:28:17.020 --> 00:28:20.035 align:middle line:90% searching, rather than DFS? 00:28:20.035 --> 00:28:22.160 align:middle line:84% AUDIENCE: It depends on how you're doing your path. 00:28:22.160 --> 00:28:24.890 align:middle line:84% If you're looking for distance one minus path, 00:28:24.890 --> 00:28:27.200 align:middle line:84% and you want to find the first one that gets you there, 00:28:27.200 --> 00:28:27.783 align:middle line:90% that's better. 00:28:27.783 --> 00:28:31.515 align:middle line:84% But you're doing positive length distances in DFS. 00:28:31.515 --> 00:28:34.318 align:middle line:90% 00:28:34.318 --> 00:28:36.610 align:middle line:84% MICHAEL CUTHBERT: I'm trying to remember the exact what 00:28:36.610 --> 00:28:38.350 align:middle line:90% I remember, which one of these. 00:28:38.350 --> 00:28:40.027 align:middle line:84% AUDIENCE: A star would be even better. 00:28:40.027 --> 00:28:42.610 align:middle line:84% MICHAEL CUTHBERT: Yeah, so we'll get to these particular types 00:28:42.610 --> 00:28:43.893 align:middle line:90% of searches later. 00:28:43.893 --> 00:28:45.310 align:middle line:84% Controversy in the class, I'll try 00:28:45.310 --> 00:28:47.650 align:middle line:90% to remember exactly which one. 00:28:47.650 --> 00:28:48.760 align:middle line:90% Do we have a-- 00:28:48.760 --> 00:28:52.990 align:middle line:84% but yeah, I'll trust that we'll solve that because we're not 00:28:52.990 --> 00:28:57.170 align:middle line:84% going to be doing shortest path yet in this class. 00:28:57.170 --> 00:29:00.130 align:middle line:84% But we'll see that there's certain advantages to one 00:29:00.130 --> 00:29:01.040 align:middle line:90% versus the other. 00:29:01.040 --> 00:29:05.680 align:middle line:84% The other thing, so what's a musical thing that we want to-- 00:29:05.680 --> 00:29:07.030 align:middle line:90% how about this? 00:29:07.030 --> 00:29:14.620 align:middle line:84% Do all parts start with the same key signature? 00:29:14.620 --> 00:29:17.590 align:middle line:90% Breadth first or depth first? 00:29:17.590 --> 00:29:20.510 align:middle line:84% Which one is going to be fastest to get you your answer? 00:29:20.510 --> 00:29:21.737 align:middle line:90% [INTERPOSING VOICES] 00:29:21.737 --> 00:29:23.570 align:middle line:84% MICHAEL CUTHBERT: I heard depth and breadth. 00:29:23.570 --> 00:29:25.180 align:middle line:90% Who's on depth? 00:29:25.180 --> 00:29:26.590 align:middle line:90% Who's on breadth? 00:29:26.590 --> 00:29:27.370 align:middle line:90% Yep. 00:29:27.370 --> 00:29:28.010 align:middle line:90% OK, good. 00:29:28.010 --> 00:29:30.670 align:middle line:84% So we're going to want to have both types of searches 00:29:30.670 --> 00:29:32.710 align:middle line:90% available. 00:29:32.710 --> 00:29:37.870 align:middle line:84% So recurse will give you always a-- 00:29:37.870 --> 00:29:42.400 align:middle line:84% what do you call it-- the depth first search. 00:29:42.400 --> 00:29:45.440 align:middle line:84% There's another one that we're going to have. 00:29:45.440 --> 00:29:49.420 align:middle line:84% And you're going to see it's the flatten operation. 00:29:49.420 --> 00:29:50.920 align:middle line:84% And you're going to see it sometimes 00:29:50.920 --> 00:29:54.262 align:middle line:84% in my old slides I haven't figured out how to update, 00:29:54.262 --> 00:29:55.190 align:middle line:90% dot flat. 00:29:55.190 --> 00:29:58.960 align:middle line:90% But it used to be a property. 00:29:58.960 --> 00:30:02.210 align:middle line:84% That is to say, you didn't need the calls called flat. 00:30:02.210 --> 00:30:05.080 align:middle line:84% Now it's a method called flatten, I think. 00:30:05.080 --> 00:30:06.650 align:middle line:90% There were two reasons for this. 00:30:06.650 --> 00:30:09.860 align:middle line:90% One, if anybody has a new-- 00:30:09.860 --> 00:30:13.190 align:middle line:84% uses an IDE, like VS Code or PyCharm, 00:30:13.190 --> 00:30:16.520 align:middle line:84% or something like that, which I highly encourage you to do-- 00:30:16.520 --> 00:30:21.230 align:middle line:84% it's nothing elite to use VIM anymore in life-- 00:30:21.230 --> 00:30:26.553 align:middle line:84% then a lot of those will now go through and call and check 00:30:26.553 --> 00:30:28.470 align:middle line:84% every one of the properties at a certain point 00:30:28.470 --> 00:30:29.850 align:middle line:90% so it can repeat for you. 00:30:29.850 --> 00:30:35.930 align:middle line:84% And flat ended up being for a very, very large score, very 00:30:35.930 --> 00:30:37.320 align:middle line:90% space and time sensitive. 00:30:37.320 --> 00:30:39.690 align:middle line:84% And so once I upgraded to a thing, 00:30:39.690 --> 00:30:43.410 align:middle line:84% I realized, OK, that can't work anymore, that flat. 00:30:43.410 --> 00:30:44.330 align:middle line:90% So we had to do this. 00:30:44.330 --> 00:30:47.360 align:middle line:84% I also wanted to make it a few more letters 00:30:47.360 --> 00:30:51.180 align:middle line:84% so that people would stop calling flat instead of recurse, 00:30:51.180 --> 00:30:52.980 align:middle line:84% just because it was less to type. 00:30:52.980 --> 00:30:56.370 align:middle line:84% So now they're much more equal, flatten. 00:30:56.370 --> 00:30:59.450 align:middle line:84% And what flatten does is it gives you 00:30:59.450 --> 00:31:03.110 align:middle line:84% the option of doing everything first 00:31:03.110 --> 00:31:06.780 align:middle line:84% that's at the same offset of everything. 00:31:06.780 --> 00:31:08.240 align:middle line:90% So we start with-- 00:31:08.240 --> 00:31:10.440 align:middle line:84% I think I have an animation on this-- 00:31:10.440 --> 00:31:13.010 align:middle line:90% the metadata, again. 00:31:13.010 --> 00:31:19.970 align:middle line:84% Let me get one clef, next clef, both the time 00:31:19.970 --> 00:31:22.560 align:middle line:84% signatures, everything that's at the same point. 00:31:22.560 --> 00:31:24.710 align:middle line:84% When you have a half note here, we'll 00:31:24.710 --> 00:31:28.920 align:middle line:84% get both quarter notes before getting to the other thing. 00:31:28.920 --> 00:31:32.870 align:middle line:84% The other thing that flatten does that's different 00:31:32.870 --> 00:31:37.852 align:middle line:84% is you'll see the offsets are now, because it's flattened, 00:31:37.852 --> 00:31:44.150 align:middle line:84% they're now all relative to the start of the score. 00:31:44.150 --> 00:31:49.800 align:middle line:84% So because of this, they're implemented in different ways. 00:31:49.800 --> 00:31:53.780 align:middle line:84% Recurse the breadth first search just has 00:31:53.780 --> 00:31:57.450 align:middle line:84% a little pointer that's going around, figuring out where I am, 00:31:57.450 --> 00:32:00.680 align:middle line:84% figuring out how to go back up to the next hierarchy level, 00:32:00.680 --> 00:32:02.340 align:middle line:90% and walk around, and do this. 00:32:02.340 --> 00:32:06.850 align:middle line:84% So it's very, very fast and not very memory intensive. 00:32:06.850 --> 00:32:10.050 align:middle line:84% The flatten, on the other hand, in order 00:32:10.050 --> 00:32:12.540 align:middle line:84% to compute where everything should be 00:32:12.540 --> 00:32:15.520 align:middle line:84% and which one is actually coming next into this hierarchy, 00:32:15.520 --> 00:32:18.060 align:middle line:84% and for historical reasons, flatten 00:32:18.060 --> 00:32:21.900 align:middle line:84% will take that same score and put it 00:32:21.900 --> 00:32:28.180 align:middle line:84% all into a new score object, a new thing, but with-- 00:32:28.180 --> 00:32:31.080 align:middle line:84% it also removes all the parts and stuff. 00:32:31.080 --> 00:32:33.820 align:middle line:84% Flatten, there are no parts or anything. 00:32:33.820 --> 00:32:36.790 align:middle line:84% There's just the things, just the leaf nodes at the end. 00:32:36.790 --> 00:32:40.720 align:middle line:84% So you'll get the clef, the other clef, the time signature, 00:32:40.720 --> 00:32:47.850 align:middle line:84% the other time signature, and so on, all in a new stream object. 00:32:47.850 --> 00:32:50.640 align:middle line:84% And this is the first time when I 00:32:50.640 --> 00:32:53.460 align:middle line:84% was saying that a note might have more than one 00:32:53.460 --> 00:32:57.240 align:middle line:84% offset, because this is the same. 00:32:57.240 --> 00:32:58.170 align:middle line:90% Oops. 00:32:58.170 --> 00:33:02.470 align:middle line:84% This quarter note here is the same as that quarter note there. 00:33:02.470 --> 00:33:06.653 align:middle line:84% So dot offset will be changing as this happens. 00:33:06.653 --> 00:33:09.210 align:middle line:90% 00:33:09.210 --> 00:33:12.640 align:middle line:84% This is something that will occasionally bite you, 00:33:12.640 --> 00:33:14.970 align:middle line:90% but usually not. 00:33:14.970 --> 00:33:18.100 align:middle line:84% Which offset does it tell we need to put dot offset? 00:33:18.100 --> 00:33:22.590 align:middle line:84% It tells you whatever the offset is in the last stream 00:33:22.590 --> 00:33:28.260 align:middle line:84% that you iterated over that has that object in it. 00:33:28.260 --> 00:33:31.355 align:middle line:90% So we call that the active site. 00:33:31.355 --> 00:33:34.080 align:middle line:90% 00:33:34.080 --> 00:33:38.045 align:middle line:84% So it tells you the offset in its active site. 00:33:38.045 --> 00:33:40.800 align:middle line:90% 00:33:40.800 --> 00:33:44.430 align:middle line:84% You will find that it's often you're 00:33:44.430 --> 00:33:48.420 align:middle line:84% looking at something in a flattened stream that 00:33:48.420 --> 00:33:50.530 align:middle line:90% should say flattened up there. 00:33:50.530 --> 00:33:54.840 align:middle line:84% And you want to know something about, oh, Professor Cuthbert 00:33:54.840 --> 00:33:59.430 align:middle line:84% said, get me all of the notes between offset 5 and 7, 00:33:59.430 --> 00:34:02.740 align:middle line:84% and tell me what measure they're in. 00:34:02.740 --> 00:34:03.550 align:middle line:90% Shoot. 00:34:03.550 --> 00:34:08.199 align:middle line:84% We've gotten all things 5 and 7 from the beginning of the score. 00:34:08.199 --> 00:34:10.449 align:middle line:84% The problem is we've lost all the measure 00:34:10.449 --> 00:34:11.690 align:middle line:90% information over here. 00:34:11.690 --> 00:34:15.310 align:middle line:84% So there is a property on all streams, dot derivation, 00:34:15.310 --> 00:34:18.219 align:middle line:84% dot origin, which will take you back 00:34:18.219 --> 00:34:21.260 align:middle line:84% to the original, the place where it came from, 00:34:21.260 --> 00:34:22.639 align:middle line:90% so the pre flattened stream. 00:34:22.639 --> 00:34:26.770 align:middle line:84% And that's something you're going to be working with a lot. 00:34:26.770 --> 00:34:28.929 align:middle line:84% This is an ontological choice I've 00:34:28.929 --> 00:34:33.130 align:middle line:84% made on how things are related, how flattened versions of scores 00:34:33.130 --> 00:34:38.260 align:middle line:84% have a derivation to the origin of the original score. 00:34:38.260 --> 00:34:42.590 align:middle line:84% Now I'll take questions on anything. 00:34:42.590 --> 00:34:43.550 align:middle line:90% It's pretty confusing. 00:34:43.550 --> 00:34:44.600 align:middle line:90% It's a lot to jump in. 00:34:44.600 --> 00:34:45.230 align:middle line:90% Yeah, Adam. 00:34:45.230 --> 00:34:48.280 align:middle line:84% AUDIENCE: Last time, what was BOEHME in the German anthem 00:34:48.280 --> 00:34:49.017 align:middle line:90% encoding? 00:34:49.017 --> 00:34:50.350 align:middle line:90% MICHAEL CUTHBERT: What was what? 00:34:50.350 --> 00:34:52.909 align:middle line:84% AUDIENCE: At the very, very top, I said it was the composer. 00:34:52.909 --> 00:34:54.076 align:middle line:90% MICHAEL CUTHBERT: Oh, Bohem. 00:34:54.076 --> 00:34:56.139 align:middle line:84% OK, so we're jumping quite a bit back. 00:34:56.139 --> 00:35:00.150 align:middle line:84% It's the location of Bohemian, originally, a Bohemian song. 00:35:00.150 --> 00:35:04.120 align:middle line:90% 00:35:04.120 --> 00:35:07.190 align:middle line:84% That was a pop quiz to see what I remembered. 00:35:07.190 --> 00:35:07.690 align:middle line:90% Great. 00:35:07.690 --> 00:35:10.370 align:middle line:90% 00:35:10.370 --> 00:35:15.640 align:middle line:84% Any other questions on this material specifically, and then 00:35:15.640 --> 00:35:16.363 align:middle line:90% on anything? 00:35:16.363 --> 00:35:23.350 align:middle line:90% 00:35:23.350 --> 00:35:31.600 align:middle line:84% OK, well, let's start by having a little bit of programming 00:35:31.600 --> 00:35:33.730 align:middle line:90% exercise time. 00:35:33.730 --> 00:35:40.150 align:middle line:84% We have this Bach chorale BWV 66.6. 00:35:40.150 --> 00:35:41.390 align:middle line:90% Are there more? 00:35:41.390 --> 00:35:42.280 align:middle line:90% Yep, go ahead. 00:35:42.280 --> 00:35:44.660 align:middle line:84% AUDIENCE: So does flatten mutate the object? 00:35:44.660 --> 00:35:47.950 align:middle line:84% MICHAEL CUTHBERT: So flatten mutates-- 00:35:47.950 --> 00:35:52.150 align:middle line:84% yes, it mutates something on every object called 00:35:52.150 --> 00:35:55.220 align:middle line:84% sites that keeps track of where things are, 00:35:55.220 --> 00:35:58.400 align:middle line:90% but it does not change a thing. 00:35:58.400 --> 00:36:00.770 align:middle line:84% There were some choices that, now 00:36:00.770 --> 00:36:03.955 align:middle line:84% that Music21 is 20 years old almost, 00:36:03.955 --> 00:36:06.330 align:middle line:84% there are some things that I would have done differently. 00:36:06.330 --> 00:36:09.590 align:middle line:84% And I think it's probably time for somebody who's 00:36:09.590 --> 00:36:12.290 align:middle line:84% younger and more ambitious and wants 00:36:12.290 --> 00:36:16.080 align:middle line:84% to do something for the next 20 years to come up with things, 00:36:16.080 --> 00:36:19.730 align:middle line:84% because I did not listen to our great software engineering 00:36:19.730 --> 00:36:24.110 align:middle line:84% Professor Peter Jackson's warnings against mutability 00:36:24.110 --> 00:36:26.160 align:middle line:84% in objects as well as I should have. 00:36:26.160 --> 00:36:29.070 align:middle line:84% And now, I'm trying to make more things immutable. 00:36:29.070 --> 00:36:31.760 align:middle line:84% But you will find that a lot of things 00:36:31.760 --> 00:36:35.270 align:middle line:84% will, by default, not mutate, but then can. 00:36:35.270 --> 00:36:36.810 align:middle line:90% And objects can be mutated. 00:36:36.810 --> 00:36:37.950 align:middle line:90% So that's a great question. 00:36:37.950 --> 00:36:40.730 align:middle line:84% Everyone knows mutable versus immutable objects. 00:36:40.730 --> 00:36:42.200 align:middle line:90% You can change, you can not. 00:36:42.200 --> 00:36:43.940 align:middle line:90% Lists are-- 00:36:43.940 --> 00:36:44.910 align:middle line:90% AUDIENCE: Mutable. 00:36:44.910 --> 00:36:46.760 align:middle line:84% MICHAEL CUTHBERT: What is the equivalent of a list in Python 00:36:46.760 --> 00:36:47.623 align:middle line:90% that is immutable? 00:36:47.623 --> 00:36:48.290 align:middle line:90% AUDIENCE: Tuple. 00:36:48.290 --> 00:36:49.710 align:middle line:90% MICHAEL CUTHBERT: Tuple, good. 00:36:49.710 --> 00:36:50.520 align:middle line:90% You all say tuple. 00:36:50.520 --> 00:36:52.710 align:middle line:84% Here I always learned it as tuple, but tuple. 00:36:52.710 --> 00:36:53.780 align:middle line:90% Great. 00:36:53.780 --> 00:36:55.760 align:middle line:90% Super. 00:36:55.760 --> 00:36:59.960 align:middle line:84% So any other questions before I go on to my question for you 00:36:59.960 --> 00:37:02.960 align:middle line:90% about Bach? 00:37:02.960 --> 00:37:09.120 align:middle line:84% OK, here is the question for you to answer. 00:37:09.120 --> 00:37:10.920 align:middle line:84% And let's do this in groups of two, 00:37:10.920 --> 00:37:13.800 align:middle line:84% because it's much more fun to be talking to. 00:37:13.800 --> 00:37:19.760 align:middle line:84% Does Bach use more ascending notes 00:37:19.760 --> 00:37:28.650 align:middle line:84% or descending notes, descending notes, or about the same? 00:37:28.650 --> 00:37:32.960 align:middle line:84% You might think the piece doesn't start off, Hallelujah, 00:37:32.960 --> 00:37:36.630 align:middle line:84% and end all [DEEP MUMBLING], and it doesn't go the opposite, 00:37:36.630 --> 00:37:39.750 align:middle line:84% so it must be about the same maybe, but we'll see. 00:37:39.750 --> 00:37:42.500 align:middle line:90% So talk. 00:37:42.500 --> 00:37:45.950 align:middle line:84% Everyone know who they're going to be paired up with? 00:37:45.950 --> 00:37:46.700 align:middle line:90% See pairs. 00:37:46.700 --> 00:37:49.500 align:middle line:84% It's easier if you're sitting on think, sit paired. 00:37:49.500 --> 00:37:50.000 align:middle line:90% Great. 00:37:50.000 --> 00:37:53.990 align:middle line:84% So start talking about how are you going to do 00:37:53.990 --> 00:37:56.100 align:middle line:90% this and what which type of-- 00:37:56.100 --> 00:37:57.850 align:middle line:84% AUDIENCE: I think I have a quick question. 00:37:57.850 --> 00:38:00.787 align:middle line:90% Why does flattening show? 00:38:00.787 --> 00:38:01.870 align:middle line:90% MICHAEL CUTHBERT: Flatten? 00:38:01.870 --> 00:38:03.090 align:middle line:90% Why does flatten show? 00:38:03.090 --> 00:38:05.838 align:middle line:90% [INTERPOSING VOICES] 00:38:05.838 --> 00:38:08.370 align:middle line:84% MICHAEL CUTHBERT: Because it's able to-- 00:38:08.370 --> 00:38:12.070 align:middle line:84% ah, because recurse is not a stream. 00:38:12.070 --> 00:38:14.310 align:middle line:84% Yeah, so I should say, recurse just 00:38:14.310 --> 00:38:16.510 align:middle line:84% gives you an iterator around that. 00:38:16.510 --> 00:38:20.610 align:middle line:84% You could do recurse thing, and then there's 00:38:20.610 --> 00:38:22.790 align:middle line:84% a dot stream that you can put onto it, 00:38:22.790 --> 00:38:24.040 align:middle line:90% and that'll give you a stream. 00:38:24.040 --> 00:38:26.200 align:middle line:84% But it's just going to give you the same thing you started with, 00:38:26.200 --> 00:38:27.220 align:middle line:90% because yeah. 00:38:27.220 --> 00:38:29.252 align:middle line:90% [INTERPOSING VOICES] 00:38:29.252 --> 00:38:30.460 align:middle line:90% MICHAEL CUTHBERT: No, no, no. 00:38:30.460 --> 00:38:31.510 align:middle line:90% Then do it then. 00:38:31.510 --> 00:38:32.330 align:middle line:90% Yeah, thank you. 00:38:32.330 --> 00:38:32.830 align:middle line:90% Thank you. 00:38:32.830 --> 00:38:34.530 align:middle line:84% Always say, we're going to talk first 00:38:34.530 --> 00:38:37.012 align:middle line:84% about how to do it then implement, but talk. 00:38:37.012 --> 00:38:38.850 align:middle line:90% [INTERPOSING VOICES] 00:38:38.850 --> 00:38:40.260 align:middle line:90% MICHAEL CUTHBERT: It's in class. 00:38:40.260 --> 00:38:42.960 align:middle line:84% I don't care however you'd like to do it. 00:38:42.960 --> 00:38:45.820 align:middle line:84% But always start talking then implementing. 00:38:45.820 --> 00:38:48.930 align:middle line:90% 00:38:48.930 --> 00:38:51.690 align:middle line:84% OK I'm hearing the discussion start 00:38:51.690 --> 00:38:53.800 align:middle line:84% dying down and hearing some clicks. 00:38:53.800 --> 00:38:56.610 align:middle line:84% You can keep talking, but just an informal poll. 00:38:56.610 --> 00:39:03.690 align:middle line:84% Which groups are on team flatten? 00:39:03.690 --> 00:39:05.740 align:middle line:90% We got one, two, three. 00:39:05.740 --> 00:39:06.460 align:middle line:90% Good, good. 00:39:06.460 --> 00:39:09.430 align:middle line:84% Which groups are on team recurse, is the best way? 00:39:09.430 --> 00:39:10.800 align:middle line:90% Good, good, good. 00:39:10.800 --> 00:39:13.980 align:middle line:84% And which groups are in team for thing, and thing, and thing, 00:39:13.980 --> 00:39:16.620 align:middle line:90% and thing, and thing? 00:39:16.620 --> 00:39:18.520 align:middle line:84% No, just there was a smile with that one. 00:39:18.520 --> 00:39:20.260 align:middle line:90% So keep going. 00:39:20.260 --> 00:39:23.020 align:middle line:84% There's ways to keep working on it. 00:39:23.020 --> 00:39:26.380 align:middle line:84% I think you'll find there's one that's better than the other. 00:39:26.380 --> 00:39:29.610 align:middle line:84% But we'll figure out which one that is. 00:39:29.610 --> 00:39:31.710 align:middle line:90% [INTERPOSING VOICES] 00:39:31.710 --> 00:39:34.805 align:middle line:90% 00:39:34.805 --> 00:39:36.930 align:middle line:84% MICHAEL CUTHBERT: And if you're lucky to be sitting 00:39:36.930 --> 00:39:39.130 align:middle line:84% next to a group that's on the different team, 00:39:39.130 --> 00:39:41.280 align:middle line:84% maybe talk across groups and figure out. 00:39:41.280 --> 00:39:46.570 align:middle line:84% We'll dialogue across religions and political views. 00:39:46.570 --> 00:39:49.630 align:middle line:90% [INTERPOSING VOICES] 00:39:49.630 --> 00:39:51.930 align:middle line:84% MICHAEL CUTHBERT: I'm going to interrupt for one second 00:39:51.930 --> 00:39:54.580 align:middle line:84% to say something that I've heard. 00:39:54.580 --> 00:39:56.973 align:middle line:90% Just a second. 00:39:56.973 --> 00:39:57.890 align:middle line:90% Yeah, just one second. 00:39:57.890 --> 00:40:00.550 align:middle line:84% Can I interrupt for one second to say something I have heard 00:40:00.550 --> 00:40:01.720 align:middle line:90% from two different groups? 00:40:01.720 --> 00:40:03.520 align:middle line:90% Matthew. 00:40:03.520 --> 00:40:05.770 align:middle line:84% Introduced for two different groups. 00:40:05.770 --> 00:40:07.760 align:middle line:84% I have heard this, something like, oh, 00:40:07.760 --> 00:40:08.780 align:middle line:90% but think of the memory. 00:40:08.780 --> 00:40:11.810 align:middle line:84% We're going to have to keep a reference to the previous note. 00:40:11.810 --> 00:40:14.900 align:middle line:84% What is to keep a reference to the previous note? 00:40:14.900 --> 00:40:17.830 align:middle line:84% What is the big O memory consideration 00:40:17.830 --> 00:40:20.420 align:middle line:90% that we're thinking about? 00:40:20.420 --> 00:40:20.920 align:middle line:90% AUDIENCE: 1? 00:40:20.920 --> 00:40:21.420 align:middle line:90% AUDIENCE: 1? 00:40:21.420 --> 00:40:22.810 align:middle line:90% MICHAEL CUTHBERT: 1. 00:40:22.810 --> 00:40:23.870 align:middle line:90% Do we care about? 00:40:23.870 --> 00:40:25.750 align:middle line:90% 0 of 1 memory? 00:40:25.750 --> 00:40:26.330 align:middle line:90% AUDIENCE: No. 00:40:26.330 --> 00:40:27.800 align:middle line:90% MICHAEL CUTHBERT: No, we do not. 00:40:27.800 --> 00:40:28.300 align:middle line:90% Good. 00:40:28.300 --> 00:40:29.510 align:middle line:90% Keep going with that. 00:40:29.510 --> 00:40:31.150 align:middle line:84% Just wanted to make sure that we had 00:40:31.150 --> 00:40:34.450 align:middle line:84% that we don't care about 0 of 1 operations very often. 00:40:34.450 --> 00:40:35.727 align:middle line:90% Occasionally. 00:40:35.727 --> 00:40:37.060 align:middle line:90% AUDIENCE: Is it just this piece? 00:40:37.060 --> 00:40:38.477 align:middle line:84% MICHAEL CUTHBERT: Just this piece. 00:40:38.477 --> 00:40:39.331 align:middle line:90% Oh. 00:40:39.331 --> 00:40:40.480 align:middle line:90% It was just this. 00:40:40.480 --> 00:40:45.970 align:middle line:84% I just heard, is it just this piece or all of Bach? 00:40:45.970 --> 00:40:48.050 align:middle line:84% Just this piece is what I'm asking for, 00:40:48.050 --> 00:40:58.790 align:middle line:84% but you could do for chorale in corpus dot-- 00:40:58.790 --> 00:41:01.215 align:middle line:90% [INTERPOSING VOICES] 00:41:01.215 --> 00:41:08.740 align:middle line:90% 00:41:08.740 --> 00:41:14.040 align:middle line:84% MICHAEL CUTHBERT: So you, Derek and Vincent, if you wanted to, 00:41:14.040 --> 00:41:16.960 align:middle line:84% there is a for loop you can do above it. 00:41:16.960 --> 00:41:20.680 align:middle line:84% And since we've unlocked corpus, that will give you all. 00:41:20.680 --> 00:41:21.590 align:middle line:90% Looking good. 00:41:21.590 --> 00:41:22.780 align:middle line:90% Looking good. 00:41:22.780 --> 00:41:26.270 align:middle line:84% So if anybody's finished and has gotten a thing, 00:41:26.270 --> 00:41:29.060 align:middle line:84% oh, a couple questions once you have that. 00:41:29.060 --> 00:41:31.070 align:middle line:90% They're not exactly the same. 00:41:31.070 --> 00:41:31.880 align:middle line:90% I'll say that. 00:41:31.880 --> 00:41:35.690 align:middle line:84% And what are some features in the chorale that explain that? 00:41:35.690 --> 00:41:43.070 align:middle line:84% The other thing you could do is do this for all 360 chorales. 00:41:43.070 --> 00:41:46.480 align:middle line:90% [INTERPOSING VOICES] 00:41:46.480 --> 00:41:49.925 align:middle line:90% 00:41:49.925 --> 00:41:52.050 align:middle line:84% MICHAEL CUTHBERT: That's a lowercase C in chorales. 00:41:52.050 --> 00:41:55.100 align:middle line:90% [INTERPOSING VOICES] 00:41:55.100 --> 00:41:59.480 align:middle line:90% 00:41:59.480 --> 00:42:02.670 align:middle line:84% MICHAEL CUTHBERT: Corpus dot corrals dot Iterator. 00:42:02.670 --> 00:42:12.140 align:middle line:84% Just before we go, who is still on team flatten? 00:42:12.140 --> 00:42:13.710 align:middle line:90% You used flatten a little bit? 00:42:13.710 --> 00:42:14.382 align:middle line:90% OK. 00:42:14.382 --> 00:42:17.750 align:middle line:84% And actually, it will say, who used flatten anywhere 00:42:17.750 --> 00:42:18.800 align:middle line:90% in the score? 00:42:18.800 --> 00:42:22.070 align:middle line:84% And who used recurse anywhere in their score? 00:42:22.070 --> 00:42:22.770 align:middle line:90% OK. 00:42:22.770 --> 00:42:29.300 align:middle line:84% I'm curious, how did flatten work for getting this? 00:42:29.300 --> 00:42:31.590 align:middle line:84% AUDIENCE: We had to say change or first times flatten, 00:42:31.590 --> 00:42:33.830 align:middle line:90% and it's the same for ascending. 00:42:33.830 --> 00:42:35.520 align:middle line:84% And then for descending, we're off by 2. 00:42:35.520 --> 00:42:36.770 align:middle line:90% MICHAEL CUTHBERT: Interesting. 00:42:36.770 --> 00:42:40.160 align:middle line:84% I'll be curious to see how that happened. 00:42:40.160 --> 00:42:41.930 align:middle line:90% Great. 00:42:41.930 --> 00:42:44.130 align:middle line:84% So I think we're wrapping up a bit. 00:42:44.130 --> 00:42:47.060 align:middle line:90% You can keep working, obviously. 00:42:47.060 --> 00:42:47.790 align:middle line:90% What is it? 00:42:47.790 --> 00:42:50.580 align:middle line:84% Item 9 on your thing, sound to score, 00:42:50.580 --> 00:42:53.900 align:middle line:84% it's one of my favorite things to teach in class because it's 00:42:53.900 --> 00:42:54.870 align:middle line:90% really, really fun. 00:42:54.870 --> 00:42:58.430 align:middle line:84% But I have made a video so we can save some time outside. 00:42:58.430 --> 00:43:00.230 align:middle line:90% And that, I'll add that. 00:43:00.230 --> 00:43:03.650 align:middle line:84% That's about a 10 minute to watch. 00:43:03.650 --> 00:43:07.260 align:middle line:84% Trying to make it quite a bit easier on this weekend. 00:43:07.260 --> 00:43:08.820 align:middle line:84% Try to make it a little bit lighter, 00:43:08.820 --> 00:43:12.530 align:middle line:84% so it's just some interesting added things 00:43:12.530 --> 00:43:13.680 align:middle line:90% that are happening there. 00:43:13.680 --> 00:43:16.550 align:middle line:84% And for the first time, I'm going 00:43:16.550 --> 00:43:21.170 align:middle line:84% to really recommend that you read the Music21 user's guide 00:43:21.170 --> 00:43:22.230 align:middle line:90% chapters. 00:43:22.230 --> 00:43:25.045 align:middle line:84% There's an optional one, Chapter 26 at the end. 00:43:25.045 --> 00:43:27.170 align:middle line:84% You don't need to read it because it's a little bit 00:43:27.170 --> 00:43:27.750 align:middle line:90% complex. 00:43:27.750 --> 00:43:29.850 align:middle line:84% But if you do read it and get through it, 00:43:29.850 --> 00:43:31.550 align:middle line:84% there are some tips in there that 00:43:31.550 --> 00:43:34.370 align:middle line:84% can make some aspects of the problem set 00:43:34.370 --> 00:43:37.650 align:middle line:90% 3 a little bit easier. 00:43:37.650 --> 00:43:41.845 align:middle line:84% So any other questions on what we did? 00:43:41.845 --> 00:43:42.780 align:middle line:90% One last thing. 00:43:42.780 --> 00:43:44.750 align:middle line:90% One last thing on this. 00:43:44.750 --> 00:43:47.340 align:middle line:84% I always recommend and I really, really 00:43:47.340 --> 00:43:49.690 align:middle line:90% recommend a readable code. 00:43:49.690 --> 00:43:50.800 align:middle line:90% Write readable code. 00:43:50.800 --> 00:43:53.880 align:middle line:84% Write code so that you can do this collaboration 00:43:53.880 --> 00:43:55.150 align:middle line:90% and give it to your friends. 00:43:55.150 --> 00:43:56.410 align:middle line:90% Write things like that. 00:43:56.410 --> 00:44:01.350 align:middle line:84% But one year a while back, the class 00:44:01.350 --> 00:44:05.970 align:middle line:84% did decide to go code golfing on this particular thing 00:44:05.970 --> 00:44:11.610 align:middle line:84% to see who could write the shortest code to do all this. 00:44:11.610 --> 00:44:14.340 align:middle line:90% 00:44:14.340 --> 00:44:14.890 align:middle line:90% Oops, sorry. 00:44:14.890 --> 00:44:16.270 align:middle line:84% AUDIENCE: Why did they do that to the eyes? 00:44:16.270 --> 00:44:17.770 align:middle line:84% MICHAEL CUTHBERT: Because back then, 00:44:17.770 --> 00:44:20.520 align:middle line:84% we were using Piazza for a discussion board, which 00:44:20.520 --> 00:44:21.850 align:middle line:90% used a proportional font. 00:44:21.850 --> 00:44:25.590 align:middle line:84% So using eyes made it-- also, it makes it a little bit more 00:44:25.590 --> 00:44:26.260 align:middle line:90% inscrutable. 00:44:26.260 --> 00:44:28.120 align:middle line:90% So never write code like this. 00:44:28.120 --> 00:44:32.430 align:middle line:84% But I do believe that that works if you want it. 00:44:32.430 --> 00:44:37.990 align:middle line:84% And your prof won, but see if you can beat that one. 00:44:37.990 --> 00:44:38.950 align:middle line:90% Thanks, everybody. 00:44:38.950 --> 00:44:40.500 align:middle line:90% [LAUGH] 00:44:40.500 --> 00:44:46.000 align:middle line:90%