WEBVTT 00:00:00.001 --> 00:00:04.660 Hello and welcome to Python Bytes, where we deliver news and headlines directly to your earbuds. 00:00:04.660 --> 00:00:11.280 This is episode 180, I can't believe it, recorded April 29th, 2020. It's almost Mayday. 00:00:11.280 --> 00:00:13.160 I am Brian Okken. 00:00:13.160 --> 00:00:14.120 And I'm Michael Kennedy. 00:00:14.120 --> 00:00:19.080 And this episode is brought to you by DigitalOcean, and we'll talk more about them a little later. 00:00:19.080 --> 00:00:27.920 Well, I have some very timely news, because not very long ago, a couple days ago, Ubuntu 20.04 is out. 00:00:27.920 --> 00:00:29.360 What? 00:00:29.360 --> 00:00:29.740 That's cool, right? 00:00:29.880 --> 00:00:31.040 Yeah, the new Ubuntu. 00:00:31.040 --> 00:00:33.260 And it's, why is this big news? 00:00:33.260 --> 00:00:36.480 Well, there's a lot of releases of Ubuntu and whatnot. 00:00:36.480 --> 00:00:42.940 But this is the first new LTS long-term support version in two years. 00:00:42.940 --> 00:00:49.280 So basically, this is the first real production-grade version of Ubuntu that's been out in two years. 00:00:49.280 --> 00:00:50.480 So that's a big deal, I think. 00:00:50.480 --> 00:00:51.520 Oh, yeah, really big deal. 00:00:51.520 --> 00:00:54.260 And it's got something special in it. 00:00:54.260 --> 00:00:55.000 It does. 00:00:55.000 --> 00:00:57.440 It hates legacy Python, but it loves modern Python. 00:00:58.220 --> 00:01:05.380 So one of the things that's bugged me about 1804, which is what I've been using for production, is it was stuck on 3.6. 00:01:05.380 --> 00:01:08.340 I mean, imagine April 2018. 00:01:08.760 --> 00:01:09.920 It's using Python 3.6. 00:01:09.920 --> 00:01:10.740 It didn't change. 00:01:10.740 --> 00:01:13.080 Well, what's the current version now? 00:01:13.080 --> 00:01:14.660 Well, that's Python 3.8. 00:01:14.660 --> 00:01:18.720 Sadly, 3.9 is going to be out really soon. 00:01:18.720 --> 00:01:19.980 And this is 3.8. 00:01:19.980 --> 00:01:22.240 But nonetheless, hey, 3.8 is awesome. 00:01:22.400 --> 00:01:25.260 It has a bunch of cool new features that we can use. 00:01:25.260 --> 00:01:27.400 And yeah, it comes included. 00:01:27.400 --> 00:01:29.420 I don't even think you have to pip install Python. 00:01:29.560 --> 00:01:30.880 I think 3.8 is already there. 00:01:30.880 --> 00:01:31.640 That's really cool. 00:01:31.640 --> 00:01:31.880 Yeah. 00:01:31.880 --> 00:01:37.580 And to get legacy Python, you can get it, but you have to go like apt install it explicitly to say, no, no, I want the old one. 00:01:37.580 --> 00:01:37.840 Yeah. 00:01:37.840 --> 00:01:39.140 Python 3.8. 00:01:39.140 --> 00:01:40.040 Automatic. 00:01:40.040 --> 00:01:41.120 It is now. 00:01:41.120 --> 00:01:41.640 f-strings everywhere. 00:01:41.640 --> 00:01:42.640 That's right. 00:01:42.720 --> 00:01:47.600 Like, it's time to hit all your code with flint and auto F-string all the things. 00:01:47.600 --> 00:01:51.820 So I upgraded all of the servers for Python bytes. 00:01:51.820 --> 00:01:53.820 The servers are pretty small and simple. 00:01:53.820 --> 00:01:57.240 But if you look at all the stuff that I'm running, there's actually a ton of servers. 00:01:57.240 --> 00:02:02.220 And I actually talked about that with Dan Bader on Talk Python episode 215. 00:02:02.220 --> 00:02:07.240 So people really want to look at what we're doing, what I'm doing here, what we're doing for Python bytes. 00:02:07.240 --> 00:02:09.380 In terms of infrastructure, they could do that. 00:02:09.420 --> 00:02:12.880 But upgraded a bunch of servers to 20.04. 00:02:12.880 --> 00:02:15.820 There's a bunch of stuff that kind of built up cruft. 00:02:15.820 --> 00:02:17.180 And I'm like, oh, we could do this way better. 00:02:17.180 --> 00:02:18.960 Redid all that stuff over the weekend. 00:02:18.960 --> 00:02:24.420 And so now everything's on the shiny new versions of Python 3.8 and Ubuntu 20.04. 00:02:24.420 --> 00:02:25.640 And it went really well for me. 00:02:25.640 --> 00:02:26.780 So that's great. 00:02:26.780 --> 00:02:27.180 Yeah. 00:02:27.180 --> 00:02:36.960 And the kernel has been upgraded to 5.4, which adds support for WireGuard, VPNs, better support for like Raspberry Pis and Intel and AMD hardware. 00:02:36.960 --> 00:02:38.860 New version of GNOME. 00:02:39.180 --> 00:02:43.820 You can install the desktop on top of the ZFS file system if you care about that. 00:02:43.820 --> 00:02:46.820 And you talked about DigitalOcean at the top. 00:02:46.820 --> 00:02:49.980 You can go to DigitalOcean right now and just check off. 00:02:49.980 --> 00:02:52.580 I want a new 20.04 droplet. 00:02:52.580 --> 00:02:53.160 Boom. 00:02:53.160 --> 00:02:53.720 Off it goes. 00:02:53.720 --> 00:02:54.420 That's how I got ours. 00:02:54.420 --> 00:02:55.260 Oh, that's great. 00:02:55.260 --> 00:02:55.980 Nice. 00:02:55.980 --> 00:02:56.580 Yeah. 00:02:56.580 --> 00:02:59.580 And actually, we've already had the kernel upgraded. 00:02:59.580 --> 00:03:02.400 The 5.4 kernel upgraded to like a new version. 00:03:02.400 --> 00:03:03.960 I just had to like apply some patches. 00:03:03.960 --> 00:03:06.120 So I guess it's pretty active. 00:03:06.120 --> 00:03:06.920 But here you go. 00:03:07.020 --> 00:03:09.120 So yeah, different topic. 00:03:09.120 --> 00:03:13.380 But for our servers, you have to like pay attention to kernel upgrades and stuff? 00:03:13.380 --> 00:03:13.640 Yeah. 00:03:13.800 --> 00:03:14.460 Apparently, yeah. 00:03:14.460 --> 00:03:17.120 They're not like on a platform as a service type of thing. 00:03:17.120 --> 00:03:17.840 It's not a big deal. 00:03:17.840 --> 00:03:20.280 It's pretty regularly like once a month or whatever. 00:03:20.280 --> 00:03:24.400 I'm usually logged in to one of them every couple of days doing something. 00:03:24.400 --> 00:03:27.080 And it'll say, oh, like either it's already applied. 00:03:27.080 --> 00:03:27.960 It says you got a reboot. 00:03:27.960 --> 00:03:30.760 It'll be like obvious that there's an update when you log in. 00:03:30.900 --> 00:03:34.660 And then I'm like, oh, I should just run that thing that upgrades all of them. 00:03:34.660 --> 00:03:35.340 Okay. 00:03:35.340 --> 00:03:36.620 Once I notice it. 00:03:36.620 --> 00:03:36.820 Yeah. 00:03:36.820 --> 00:03:37.680 So pretty much. 00:03:37.680 --> 00:03:37.880 Yeah. 00:03:37.880 --> 00:03:38.200 Okay. 00:03:38.200 --> 00:03:38.620 Neat. 00:03:38.620 --> 00:03:38.820 Yeah. 00:03:38.820 --> 00:03:39.140 Okay. 00:03:39.140 --> 00:03:40.800 Well, I'm going to switch hats. 00:03:40.800 --> 00:03:44.060 So I want to talk about warnings. 00:03:44.060 --> 00:03:45.900 So warning, I'm going to switch a hat. 00:03:45.900 --> 00:03:50.600 And so Reuven Lerner is a friend of the show and great guy, teaches Python. 00:03:50.600 --> 00:03:53.640 And we wrote an article called Working with Warnings in Python. 00:03:53.640 --> 00:03:57.480 And I like this because I don't think we've talked about warnings much. 00:03:57.480 --> 00:03:58.780 No, not much at all, actually. 00:03:58.780 --> 00:04:03.580 It's a good introduction, but he talks about exceptions and the class hierarchy and printouts 00:04:03.580 --> 00:04:03.980 and stuff. 00:04:03.980 --> 00:04:08.440 But if you want to like, if something goes wrong, you kind of want, you've got options 00:04:08.440 --> 00:04:12.780 of like printing out to the user or throwing an exception, but you also have warnings. 00:04:12.780 --> 00:04:15.260 And how should you treat those? 00:04:15.260 --> 00:04:16.980 And I love what he wrote. 00:04:16.980 --> 00:04:21.800 He said, most of the time, warnings are aimed at developers rather than users. 00:04:22.360 --> 00:04:25.740 Warnings in Python are sort of like the service needed light on a car. 00:04:25.740 --> 00:04:30.920 The user might know that something is wrong, but only a qualified repair person will know 00:04:30.920 --> 00:04:31.460 what to do. 00:04:31.460 --> 00:04:35.100 Developers should avoid showing warnings to end users. 00:04:35.100 --> 00:04:40.280 But one of the things that the warning system is used for is deprecation warnings. 00:04:40.280 --> 00:04:44.520 A lot of projects do this where they kind of want to get rid of a feature so they can 00:04:44.520 --> 00:04:49.480 refactor some stuff and or just doesn't fit in the API very well. 00:04:49.940 --> 00:04:54.620 So they'll deprecate it and they'll issue a deprecation warning when somebody uses it. 00:04:54.620 --> 00:04:55.320 So it's an alert. 00:04:55.320 --> 00:04:58.500 It doesn't stop working, but it alerts people to that. 00:04:58.500 --> 00:04:59.120 There's a warning. 00:04:59.120 --> 00:05:05.100 One of the things I love about warnings is by default, pytest turns on warnings. 00:05:05.100 --> 00:05:10.320 And so you can see those and you can also make them make pytest so that it fails on warnings. 00:05:10.580 --> 00:05:15.340 So this is a good thing to pay attention to, but it doesn't stop your project. 00:05:15.340 --> 00:05:16.260 That's cool. 00:05:16.260 --> 00:05:21.060 I didn't know you can make pytest, like observe and use the warnings as an error. 00:05:21.060 --> 00:05:21.460 Yeah. 00:05:21.460 --> 00:05:23.680 The warning system gives you a whole bunch of stuff. 00:05:23.680 --> 00:05:28.620 Python's warning system, it treats warnings as separate types of output so that we don't 00:05:28.620 --> 00:05:31.480 confuse them with either exceptions or printed texts. 00:05:31.840 --> 00:05:34.760 It lets us indicate what kind of warning we're sending the user. 00:05:34.760 --> 00:05:35.860 So we have different types. 00:05:35.860 --> 00:05:37.460 It's like the exception hierarchy. 00:05:37.460 --> 00:05:38.280 You can have a warning. 00:05:38.280 --> 00:05:39.340 There's a warning hierarchy. 00:05:39.340 --> 00:05:45.240 You can create your own and you can filter on them so that you can screen out stuff that 00:05:45.240 --> 00:05:48.140 you don't care about, selectively fix things. 00:05:48.140 --> 00:05:50.440 Anyway, it's a very powerful system. 00:05:50.440 --> 00:05:52.140 People should use it when they need it. 00:05:52.500 --> 00:05:57.780 The article goes on to give specifics on the syntax of how to use them, how to create 00:05:57.780 --> 00:06:00.260 custom warnings, and how to filter on them. 00:06:00.260 --> 00:06:01.540 And it's a good intro. 00:06:01.540 --> 00:06:05.240 Yeah, this looks super interesting and like something I should be paying more attention to 00:06:05.240 --> 00:06:06.440 than I have so far. 00:06:06.440 --> 00:06:07.960 Is this something I'm not really using? 00:06:07.960 --> 00:06:09.880 I'm more a consumer of warnings. 00:06:09.880 --> 00:06:13.800 I'm like, oh, that library, it started issuing warnings about something. 00:06:13.800 --> 00:06:19.720 And sometimes it's really frustrating because it's like the library being used by the library 00:06:19.720 --> 00:06:22.960 I'm actually trying to use is doing something wrong. 00:06:22.960 --> 00:06:25.620 It says, well, this is going to be deprecated and now you've got to do this. 00:06:25.620 --> 00:06:27.340 I'm like, well, but I'm not doing that. 00:06:27.340 --> 00:06:28.360 I don't want to see this. 00:06:28.360 --> 00:06:32.060 But nonetheless, it looks like way simpler than maybe. 00:06:32.060 --> 00:06:32.920 I just haven't looked at it. 00:06:32.920 --> 00:06:33.480 It looks great. 00:06:33.480 --> 00:06:34.520 So I should use this more. 00:06:34.520 --> 00:06:40.740 One of the cool use cases that I heard recently is using pytest warnings or pytest's knowledge 00:06:40.740 --> 00:06:45.640 of warnings and testing your system when you're upgrading Python so that you can say, 00:06:45.640 --> 00:06:48.800 oh, when we're, because Python will deprecate things too. 00:06:49.360 --> 00:06:55.120 And then you can have a heads up that you need to start fixing your code because it'll 00:06:55.120 --> 00:06:56.320 pinpoint you exactly. 00:06:56.320 --> 00:06:57.660 It's kind of like the exception system. 00:06:57.660 --> 00:06:59.140 It tells you exactly where it's coming from. 00:06:59.140 --> 00:07:01.120 So yeah, that is really nice. 00:07:01.120 --> 00:07:02.960 Do you want to know something else that's nice? 00:07:02.960 --> 00:07:03.580 DigitalOcean. 00:07:03.580 --> 00:07:05.000 DigitalOcean is very nice. 00:07:05.000 --> 00:07:14.160 And DigitalOcean just launched their virtual private cloud or VPC system and new trust platform. 00:07:14.160 --> 00:07:15.420 Ooh, a trust platform. 00:07:15.660 --> 00:07:19.960 Together, these make it easier to architect and run serious business applications with 00:07:19.960 --> 00:07:22.280 even stronger security and confidence. 00:07:22.280 --> 00:07:29.220 VPC allows you to create multiple private networks for your account or your team instead of having 00:07:29.220 --> 00:07:30.380 just one private network. 00:07:30.380 --> 00:07:37.600 DigitalOcean can auto-generate your private networks, IP address range, or you can specify 00:07:37.600 --> 00:07:38.900 your own IPs. 00:07:39.140 --> 00:07:44.240 You can now configure droplets to have, to behave as internet gateways. 00:07:44.240 --> 00:07:44.880 That's cool. 00:07:44.880 --> 00:07:45.160 Yeah. 00:07:45.160 --> 00:07:46.380 It's like your own little baby internet. 00:07:46.380 --> 00:07:47.040 Yeah. 00:07:47.040 --> 00:07:47.580 That's neat. 00:07:47.580 --> 00:07:53.160 And a trust platform is a new microsite that provides one place to get all your security 00:07:53.160 --> 00:07:58.640 and privacy questions answered and download our available security certifications. 00:07:59.280 --> 00:08:01.600 DigitalOcean is your trusted partner in the cloud. 00:08:01.600 --> 00:08:08.240 Visit pythonbytes.fm/DigitalOcean to get $100 credit for new users to build something 00:08:08.240 --> 00:08:08.540 awesome. 00:08:08.540 --> 00:08:08.800 Yeah. 00:08:08.800 --> 00:08:09.500 We love it. 00:08:09.500 --> 00:08:14.160 Like I just said at the outset, put Ubuntu 20.04 on there, and it's been working great 00:08:14.160 --> 00:08:14.760 for so many years. 00:08:14.760 --> 00:08:20.800 Now, one thing that I ran across, there's a few little libraries that are so simple, and 00:08:20.800 --> 00:08:24.720 yet when you come across them, you're like, oh yes, this is so cool. 00:08:24.720 --> 00:08:31.320 One of those that I go on and on about is unsync, how that unifies all the different APIs that 00:08:31.320 --> 00:08:37.840 do asynchronous programming, like asyncio, threaded stuff, multiprocessing stuff, and whatnot. 00:08:37.840 --> 00:08:38.220 Right? 00:08:38.220 --> 00:08:41.480 So this is one I think that kind of is like that. 00:08:41.480 --> 00:08:46.720 It's not about unification, but it's about solving a problem in a way that's kind of transparent 00:08:46.720 --> 00:08:52.200 to the user, but is really, really awesome because it just adds some nice durability to 00:08:52.200 --> 00:08:52.640 your code. 00:08:52.640 --> 00:08:59.480 So there's different levels of like exception handling if you look at it, right? 00:08:59.480 --> 00:09:05.060 So if you look at code, there's probably like the beginner level that has no try except blocks 00:09:05.060 --> 00:09:06.000 anywhere in the code. 00:09:06.000 --> 00:09:08.220 It's just like, I don't know what you call it. 00:09:08.220 --> 00:09:09.560 Is that optimistic programming? 00:09:09.560 --> 00:09:11.700 Like I don't need to do error handling. 00:09:11.700 --> 00:09:12.380 It's going to be fine. 00:09:12.380 --> 00:09:13.160 Everything's fine. 00:09:13.160 --> 00:09:13.820 This is fine. 00:09:13.820 --> 00:09:15.320 That's one way. 00:09:15.740 --> 00:09:19.440 The next level would be to say, okay, I'm going to have some exception handling. 00:09:19.440 --> 00:09:24.420 I'm going to do a try, do a bunch of stuff, except handle the error, right? 00:09:24.420 --> 00:09:24.980 That's good. 00:09:24.980 --> 00:09:26.280 And maybe you're catching different errors. 00:09:26.280 --> 00:09:27.620 Like maybe that's another level. 00:09:27.620 --> 00:09:31.940 I don't know what the making of these levels up a little bit, but even if you are catching 00:09:31.940 --> 00:09:37.100 an error, something could have gone terribly, terribly wrong and corrupted your data along 00:09:37.100 --> 00:09:37.540 the way. 00:09:37.540 --> 00:09:42.680 So there's like durable error handling and there's, it isn't technically crashing at the moment 00:09:42.680 --> 00:09:43.700 error handling, right? 00:09:43.740 --> 00:09:48.040 So the durable error handling, I don't think a lot of people think about nearly as much. 00:09:48.040 --> 00:09:53.500 So simple example is what you would maybe use a transaction for in a database is like, 00:09:53.500 --> 00:09:56.320 I'm going to transfer money from this account to that account. 00:09:56.320 --> 00:09:59.920 But what happens if the transfer to the second account fails? 00:10:00.120 --> 00:10:03.240 I want to make sure I don't actually take the money from the first account, right? 00:10:03.240 --> 00:10:07.560 Or I want to write some piece of data to a file. 00:10:07.560 --> 00:10:11.040 So I'm going to open the file and I'm going to make sure there's a try accept. 00:10:11.040 --> 00:10:12.440 I'm going to put it in a width block. 00:10:12.440 --> 00:10:13.820 So the file pointer gets closed. 00:10:13.820 --> 00:10:14.740 Everything's going to be good. 00:10:14.740 --> 00:10:17.540 I'm going to make one change and another change. 00:10:17.540 --> 00:10:20.380 And then a third change, like write these three things to the file. 00:10:20.880 --> 00:10:23.960 What if the exception happens after the second line? 00:10:23.960 --> 00:10:25.700 You've half written to the file. 00:10:25.700 --> 00:10:26.960 Now what? 00:10:26.960 --> 00:10:27.380 I don't know. 00:10:27.380 --> 00:10:27.940 Wow. 00:10:27.940 --> 00:10:28.700 That's bad, right? 00:10:28.700 --> 00:10:29.220 Yeah. 00:10:29.220 --> 00:10:31.680 So there's all these ways in which, like you still have a try accept. 00:10:31.680 --> 00:10:32.460 You still catch it. 00:10:32.460 --> 00:10:33.500 You still close the file pointer. 00:10:33.500 --> 00:10:34.260 It doesn't matter. 00:10:34.260 --> 00:10:35.080 It's corrupted, right? 00:10:35.080 --> 00:10:40.020 So there's like this another level of error handling of like kind of treating memory and 00:10:40.020 --> 00:10:44.120 files and whatnot as transaction, transactional type things, right? 00:10:44.120 --> 00:10:47.080 If there's an error, they just go back the way they were. 00:10:47.080 --> 00:10:52.280 And so this thing that this long winded introduction is about is called safer. 00:10:52.280 --> 00:10:54.280 So a safer file writer. 00:10:54.280 --> 00:10:58.140 And it's this cool, simple little thing. 00:10:58.140 --> 00:11:04.800 Instead of saying with open file name as file pointer, you say with safer dot open. 00:11:04.800 --> 00:11:06.380 File name as file pointer. 00:11:06.380 --> 00:11:08.240 And then otherwise all your code is identical. 00:11:08.240 --> 00:11:08.720 Okay. 00:11:08.720 --> 00:11:09.100 Okay. 00:11:09.100 --> 00:11:10.640 Here's what it actually does. 00:11:10.640 --> 00:11:16.280 So as you write to the file pointer, it's writing to a temporary file behind the scenes. 00:11:16.280 --> 00:11:22.800 And then if, you know, when you exit a width block, the width block, the exit, the dunder exit 00:11:22.800 --> 00:11:26.200 takes whether or not there was an error on the way out the door. 00:11:26.200 --> 00:11:31.460 So, you know, as you exit the width block, did as, am I leaving because a crash or am I leaving 00:11:31.460 --> 00:11:34.520 because everything is cool and we're done? 00:11:35.060 --> 00:11:40.240 So it uses that information to either throw away the temp file or move the temp file over 00:11:40.240 --> 00:11:42.600 top the thing you thought you were writing on. 00:11:42.600 --> 00:11:42.860 Oh. 00:11:42.860 --> 00:11:43.540 Isn't that cool? 00:11:43.540 --> 00:11:48.320 So if there's an exception in your width block, it still closes up the file pointer and everything, 00:11:48.320 --> 00:11:49.560 but your data is unchanged. 00:11:49.560 --> 00:11:53.280 It's kind of like a transaction with a roll auto rollback for files. 00:11:53.280 --> 00:11:54.060 That's pretty cool. 00:11:54.060 --> 00:11:54.660 Isn't that cool? 00:11:54.660 --> 00:11:57.060 And it's like 28 lines of code that does that little bit. 00:11:57.060 --> 00:11:57.420 Yeah. 00:11:57.420 --> 00:11:59.980 Is it any idea what the time hit is? 00:11:59.980 --> 00:12:01.160 It's got to be a little bit, but. 00:12:01.160 --> 00:12:04.840 It's pretty small because it just uses shutil to replace the file. 00:12:04.840 --> 00:12:07.480 Like it writes to the file just as you would write to the file. 00:12:07.480 --> 00:12:08.520 Okay. 00:12:08.520 --> 00:12:12.300 And then at the very end, it goes, move this file to this destination and overwrite. 00:12:12.740 --> 00:12:17.620 So it's basically adds a file move, which in an SSD is like nothing, right? 00:12:17.620 --> 00:12:18.300 Okay. 00:12:18.300 --> 00:12:19.780 It doesn't matter how big it is. 00:12:19.780 --> 00:12:24.700 It probably just like updates the, I don't know, like the table in the drive, whatever 00:12:24.700 --> 00:12:25.100 that means. 00:12:25.100 --> 00:12:26.300 Yeah. 00:12:26.300 --> 00:12:26.900 Isn't that cool? 00:12:26.900 --> 00:12:27.700 That is very cool. 00:12:27.700 --> 00:12:28.280 I like it. 00:12:28.280 --> 00:12:28.560 Yeah. 00:12:28.560 --> 00:12:31.020 So it seems so easy to use. 00:12:31.020 --> 00:12:32.980 It looks like something that might be worth looking at. 00:12:32.980 --> 00:12:34.640 So I'm linking to a couple of things. 00:12:34.640 --> 00:12:36.920 I'm linking to an article that introduces this. 00:12:36.920 --> 00:12:41.440 And in the beginning, apparently there was like some edge case where something wasn't 00:12:41.440 --> 00:12:42.240 working quite right. 00:12:42.240 --> 00:12:48.340 If you passed like an integer representing a file handle or something funky like that, it 00:12:48.340 --> 00:12:48.860 didn't deal with that. 00:12:48.860 --> 00:12:49.000 Right. 00:12:49.000 --> 00:12:54.920 So there's a, another, like an updated article that doesn't have all the motivation, but then 00:12:54.920 --> 00:12:56.280 talks about this fix. 00:12:56.280 --> 00:12:58.600 And there's also a GitHub repo and you can just pip install it. 00:12:58.600 --> 00:12:59.520 So all those things are good. 00:12:59.520 --> 00:13:03.540 And the final in this section, I'm linking to the actual 28 lines of code. 00:13:03.820 --> 00:13:04.740 Do you have that open? 00:13:04.740 --> 00:13:05.480 I did. 00:13:05.480 --> 00:13:06.480 Click on that really quick. 00:13:06.480 --> 00:13:10.060 Cause I want to talk about a couple of really interesting patterns here. 00:13:10.060 --> 00:13:15.900 Like if you wanted to study 28 lines of code that took and brought together a bunch of interesting 00:13:15.900 --> 00:13:18.020 ideas, like, Whoa, this is pretty crazy. 00:13:18.020 --> 00:13:27.020 So it has a generator expression on an infinite sequence of numbers to find the temporary file, 00:13:27.020 --> 00:13:31.520 which is pretty interesting because it just says, I'm going to call it dot one, dot two, 00:13:31.520 --> 00:13:32.040 dot three. 00:13:32.100 --> 00:13:36.180 And in case those exist, we're just going to go through all of them until one doesn't. 00:13:36.180 --> 00:13:37.440 Isn't this crazy? 00:13:37.440 --> 00:13:39.160 So that's pretty fun. 00:13:39.160 --> 00:13:43.240 And that uses shutil to copy the file over, which is pretty cool. 00:13:43.240 --> 00:13:48.700 It uses yield to automatically return the inner file pointer. 00:13:48.700 --> 00:13:54.040 So when you say with thing as whatever, even though you said safer dot open, it actually 00:13:54.040 --> 00:13:59.020 yields out the underlying pointer file pointer that came from open. 00:13:59.020 --> 00:14:02.480 And there's just a bunch of different layers of, Oh, that's interesting. 00:14:02.480 --> 00:14:03.360 Oh, that's neat. 00:14:03.580 --> 00:14:03.800 Yeah. 00:14:03.800 --> 00:14:05.300 Anyway, I think this is really clever. 00:14:05.300 --> 00:14:08.000 And it seems like a cool little library. 00:14:08.500 --> 00:14:13.220 The reason I think it would probably be useful and not going to give you a big hit. 00:14:13.220 --> 00:14:14.360 It's like, this is literally it. 00:14:14.360 --> 00:14:15.580 You can see it's creating the temp file. 00:14:15.580 --> 00:14:21.060 It writes to the temp file and then it uses OS dot rename the temp file to the actual thing. 00:14:21.520 --> 00:14:25.720 So, you know, not a whole lot of magic going on, but really quite useful. 00:14:25.720 --> 00:14:27.200 I think not a lot of code either. 00:14:27.200 --> 00:14:27.480 Yeah. 00:14:27.480 --> 00:14:27.920 Just. 00:14:27.920 --> 00:14:28.360 Yeah. 00:14:28.360 --> 00:14:28.780 Isn't that crazy? 00:14:28.780 --> 00:14:29.080 Yeah. 00:14:29.080 --> 00:14:29.620 That's pretty cool. 00:14:29.620 --> 00:14:30.100 I love it. 00:14:30.100 --> 00:14:35.180 Useful gives you that sort of durable error handling, almost like transactional files. 00:14:35.180 --> 00:14:36.900 And yet super simple. 00:14:36.900 --> 00:14:37.500 Very good. 00:14:37.500 --> 00:14:39.740 Uses unit test as its test runner, though. 00:14:39.740 --> 00:14:40.460 Oh, my God. 00:14:40.460 --> 00:14:41.100 Well, all right. 00:14:41.100 --> 00:14:43.920 I retract all of my endorsements of this thing. 00:14:43.920 --> 00:14:47.500 All right. 00:14:47.500 --> 00:14:48.220 What's the next one? 00:14:48.220 --> 00:14:48.620 Okay. 00:14:48.620 --> 00:14:49.980 I'm on the other tab. 00:14:49.980 --> 00:14:51.500 So did I distract you? 00:14:51.620 --> 00:14:52.720 Oh, yeah, you did. 00:14:52.720 --> 00:14:54.620 And new article, new hat. 00:14:54.620 --> 00:14:56.040 So code spell. 00:14:56.040 --> 00:15:03.900 So I got this from Christian Klaus, that silly little project I play with on the side called 00:15:03.900 --> 00:15:04.320 Cards. 00:15:04.320 --> 00:15:10.500 I got a pull request against the project to add a pre-commit hook to run code spell. 00:15:10.500 --> 00:15:12.720 And I had never heard of code spell. 00:15:12.720 --> 00:15:16.120 So I was excited to have a new topic for the podcast. 00:15:16.120 --> 00:15:17.840 Also, just it's as neat. 00:15:18.340 --> 00:15:19.000 So code spell. 00:15:19.000 --> 00:15:22.440 What it does is it fixes common misspellings in text files. 00:15:22.440 --> 00:15:27.940 And specifically, it's designed primarily for checking misspelled words in source code. 00:15:27.940 --> 00:15:30.880 But it can be used as other files as well. 00:15:31.100 --> 00:15:43.920 When Christian applied this to the cards project, it noticed that in one of the documentation files I've got, one of the markdown files, I had spelled arguments with an extra U in the middle of it. 00:15:44.440 --> 00:15:55.400 And one of the problems with spelling, I mean, it's embarrassing to do and distracting to have spelling errors in your code or your comments or anything. 00:15:55.660 --> 00:16:06.620 It's hard to deal with because a lot of source code doesn't have, you can't just throw normal spell checkers at source code because it'll just, it'll warn you on your variable names and all sorts of stuff. 00:16:06.620 --> 00:16:06.920 Right. 00:16:06.920 --> 00:16:08.420 You can't drop it in grammarly. 00:16:08.420 --> 00:16:09.340 That's not going to go well. 00:16:09.340 --> 00:16:10.500 It's not going to work. 00:16:10.500 --> 00:16:21.060 But so I'm really excited to try this and to start using it because if it can work for just about anything, it might be able to work for, you know, non-Python programs too as well. 00:16:21.300 --> 00:16:21.640 Why not? 00:16:21.640 --> 00:16:23.280 So yeah, it's pretty cool. 00:16:23.280 --> 00:16:24.120 Yeah, all sorts of documentation. 00:16:24.120 --> 00:16:24.540 That's cool. 00:16:24.540 --> 00:16:25.940 It's an open source project. 00:16:25.940 --> 00:16:29.520 The GitHub repo has the entire dictionary so you can scan through it. 00:16:29.520 --> 00:16:35.060 And there's ways to ignore certain words if you're like, no, that's the correct spelling and it keeps doing stuff. 00:16:35.060 --> 00:16:36.460 You can ignore it. 00:16:36.460 --> 00:16:37.060 Nice. 00:16:37.060 --> 00:16:38.140 Well, that's a really good one. 00:16:38.140 --> 00:16:50.360 The most embarrassing misspelling I've ever done in code was I'd misspelled like a namespace or a class name or package name or something like that. 00:16:50.440 --> 00:16:52.980 I can't remember quite where it was. 00:16:52.980 --> 00:17:00.200 But it was on a project I had been working on for like a year and I misspelled it, but everything was autocomplete. 00:17:00.200 --> 00:17:00.720 And so I don't care. 00:17:00.720 --> 00:17:01.340 I'm like, da, da, da. 00:17:01.340 --> 00:17:02.900 It is just like, okay, autocomplete. 00:17:02.900 --> 00:17:04.820 I'm not even like ever typing that again. 00:17:04.820 --> 00:17:05.080 Right. 00:17:05.080 --> 00:17:05.620 Yeah. 00:17:05.620 --> 00:17:07.780 I guess I just wasn't paying attention to like that. 00:17:07.780 --> 00:17:08.980 I kind of suck at spelling. 00:17:08.980 --> 00:17:11.080 That was like an extra bad case. 00:17:11.680 --> 00:17:16.120 Some new person came on the team and said, dude, why is this misspelled all over the place? 00:17:16.120 --> 00:17:17.800 And I'm like, oh, we got to fix it. 00:17:17.800 --> 00:17:22.780 But it was like other applications depended on that library and they used the misspelling. 00:17:22.780 --> 00:17:28.660 It was so bad because it was like it had become pervasive throughout like all these different things. 00:17:28.720 --> 00:17:30.920 So like we may have to leave that misspelled. 00:17:30.920 --> 00:17:32.340 I think we eventually fixed it. 00:17:32.340 --> 00:17:36.040 But it was like it was quite a bit of work considering what it should have been. 00:17:36.040 --> 00:17:37.320 That's funny. 00:17:37.320 --> 00:17:38.440 That's awesome. 00:17:38.440 --> 00:17:45.020 Well, at least you didn't have like both of the spellings be valid symbols in your program and mean completely different things. 00:17:45.180 --> 00:17:45.580 That's true. 00:17:45.580 --> 00:17:47.780 Yeah. 00:17:47.780 --> 00:17:57.900 So one of the things that's awesome about this podcast is we'll say we'll find some random thing or maybe somebody will send it to us and we'll say, oh, did you even know that this was a thing? 00:17:57.900 --> 00:17:59.020 I had never heard of this. 00:17:59.020 --> 00:18:04.680 And then like five other people shoot us a message and say, yeah, and this variation or this other thing. 00:18:04.680 --> 00:18:05.240 And that's cool. 00:18:05.240 --> 00:18:06.600 But there's also X, Y and Z. 00:18:06.600 --> 00:18:06.800 Right. 00:18:06.800 --> 00:18:07.240 Isn't that awesome? 00:18:07.240 --> 00:18:07.960 Yeah. 00:18:07.960 --> 00:18:08.640 Yeah. 00:18:08.640 --> 00:18:10.140 I learned so much by doing this. 00:18:10.140 --> 00:18:10.740 Yes, I know. 00:18:10.740 --> 00:18:14.500 We just got to throw something we vaguely know about and like people will correct us. 00:18:14.500 --> 00:18:14.820 Yeah. 00:18:14.820 --> 00:18:15.120 Awesome. 00:18:15.820 --> 00:18:25.900 So, no, seriously, we talked about profilers and I talked about scaling, how it was really nice and fast and it did memory profiling and all that. 00:18:25.900 --> 00:18:31.980 Well, friend of the show, Anthony Shaw said, hey, since you're on this kick for profilers, have you heard about Austin? 00:18:31.980 --> 00:18:35.500 To me, Austin is either a guy's name or a town in Texas. 00:18:35.500 --> 00:18:37.220 I hadn't heard about Austin. 00:18:37.220 --> 00:18:37.520 Have you? 00:18:37.520 --> 00:18:38.940 I got a neighbor named Austin. 00:18:38.940 --> 00:18:39.560 Yeah. 00:18:39.560 --> 00:18:41.140 I don't think this is the same thing. 00:18:41.580 --> 00:18:54.360 So, this is like scaling is a frame stack sampler for CPython, meaning it doesn't have like this huge effect of once you run it on your code, it doesn't become 10 times slower as instrumenting. 00:18:54.360 --> 00:18:58.240 You know, it just asks like, hey, what are you up to really quickly? 00:18:58.240 --> 00:18:59.360 So, that's cool. 00:18:59.360 --> 00:19:00.500 It's nice and fast. 00:19:00.500 --> 00:19:02.080 It also is just pure C code. 00:19:02.080 --> 00:19:06.740 There's no real dependencies like other than like the C runtime, which is in all the operating systems. 00:19:07.140 --> 00:19:13.160 So, it looks at running Python code at intervals and then it dumps out whatever it finds, which is cool. 00:19:13.160 --> 00:19:20.360 It has a really simple output, but as you will learn, it has all these interesting ways to visualize that output. 00:19:20.360 --> 00:19:24.780 So, it's sort of base, it's atomic unit of output is a flame graph. 00:19:24.780 --> 00:19:31.840 So, flame graphs are like stacked up sort of things that are colorful and they also have information. 00:19:31.920 --> 00:19:34.080 So, like the color communicates information and the height. 00:19:34.080 --> 00:19:39.440 So, it's kind of like a graph with like color bars type of thing and it has the parts of code they're running. 00:19:39.440 --> 00:19:43.160 If you want to see what that is, just click on the link and it has it right there at the top. 00:19:43.160 --> 00:19:44.060 And that's cool. 00:19:44.060 --> 00:19:54.380 So, it puts that out, but you can build other tools to analyze that or you could even make like a little player application that replays the execution of your application in like slow motion. 00:19:54.580 --> 00:19:56.760 Like replays that flame graph over time. 00:19:56.760 --> 00:19:57.380 Oh, that's neat. 00:19:57.380 --> 00:19:57.880 Isn't that cool? 00:19:57.880 --> 00:19:58.180 Yeah. 00:19:58.180 --> 00:20:05.880 So, now is where it gets really fun because there's a couple of user interfaces on top of this like simple output that can be interpreted. 00:20:05.880 --> 00:20:11.000 So, the first one is called the TUI, the Terminal User Interface. 00:20:11.000 --> 00:20:13.220 Do you see this animated in our little show notes? 00:20:13.220 --> 00:20:13.920 And we'll be in there. 00:20:13.920 --> 00:20:14.200 It's nice. 00:20:14.200 --> 00:20:15.380 Yeah, it's really cool. 00:20:15.380 --> 00:20:15.920 Yeah. 00:20:15.980 --> 00:20:17.400 So, let me try to describe it. 00:20:17.400 --> 00:20:21.720 Like imagine you've opened, I don't know, Emacs or something like that. 00:20:21.720 --> 00:20:30.120 But the top part of it shows the process information, the CPU it's using, the memory it's using, how long it's been running. 00:20:30.120 --> 00:20:38.000 And then a graph, an active like interactive flowing graph across the top of like the performance analysis. 00:20:38.360 --> 00:20:45.820 And then it has something that's a little bit like top maybe, showing you like what it's currently running, how much time it's using. 00:20:45.820 --> 00:20:49.300 Is this time being spent on a sub function call? 00:20:49.300 --> 00:20:54.960 Like did I call a thing that called request that is talking to the network and that's why it's slow because we're waiting on the internet? 00:20:54.960 --> 00:20:59.560 Or is it actually computationally my stuff running in Python or whatever, right? 00:20:59.560 --> 00:21:00.480 So, what do you think? 00:21:00.480 --> 00:21:01.000 That's cool, huh? 00:21:01.000 --> 00:21:08.600 Yeah, that bottom part reminds me of the thing that you put the process explorer on Windows where you look at all your processes. 00:21:08.600 --> 00:21:09.520 Yeah, a little bit. 00:21:09.520 --> 00:21:10.280 Like task manager. 00:21:10.280 --> 00:21:13.440 But it's actually for like your functions instead of other processes. 00:21:13.440 --> 00:21:14.440 Yeah, yeah. 00:21:14.440 --> 00:21:15.360 It's nice. 00:21:15.360 --> 00:21:15.840 That's cool. 00:21:15.840 --> 00:21:18.980 So, that's the TUI, which is going to be a popular one. 00:21:18.980 --> 00:21:20.780 But you may also want to be on the web. 00:21:20.780 --> 00:21:24.780 So, there's WebAustin, which is another example of making this for the web. 00:21:24.780 --> 00:21:36.600 So, you basically can log into wherever you're running it, connect to it, and it has a D3 flame graph that's like animated of what your web app or whatever process you're watching on that remote system is up to. 00:21:36.600 --> 00:21:39.780 So, it's kind of the same thing, but like more visual, more graphical. 00:21:39.780 --> 00:21:42.680 Like the flame graph is there and whatnot. 00:21:42.680 --> 00:21:44.820 So, that's pretty cool. 00:21:44.820 --> 00:21:46.300 People can check that one out. 00:21:46.300 --> 00:21:48.100 You can even pause it and whatnot. 00:21:48.240 --> 00:21:55.020 Then finally, there's this other format called SpeedScope, which can be visualized in other tools. 00:21:55.020 --> 00:22:00.760 And you can convert Austin output into the SpeedScope JSON format. 00:22:00.760 --> 00:22:03.680 And there's a sample for that in the repo. 00:22:03.680 --> 00:22:09.760 If you go look at that, you can load it into the SpeedScope visualizer type of things and have another way to view the data. 00:22:09.760 --> 00:22:14.460 So, this is really nice because so many of these profilers are like, we collected all this information. 00:22:14.940 --> 00:22:17.180 How would you like it as a CSV? 00:22:17.180 --> 00:22:22.320 Or how would you like it as just like random columns in a terminal? 00:22:22.320 --> 00:22:25.460 And this is so much like, I would not like it that way. 00:22:25.460 --> 00:22:30.820 I really like the visualization because it's one thing to gather the information. 00:22:30.820 --> 00:22:33.400 It's another to go, oh, I see. 00:22:33.400 --> 00:22:35.920 Right there is actually where it's slow. 00:22:35.920 --> 00:22:40.560 And if it's just a dump of a bunch of numbers, I mean, yeah, you can like sort it and whatnot. 00:22:40.560 --> 00:22:44.740 And you can use cProfile with different sorting options and get it to mean stuff. 00:22:44.900 --> 00:22:45.680 It is not the same. 00:22:45.680 --> 00:22:47.040 It's like, aha, there's the picture. 00:22:47.040 --> 00:22:47.520 I see. 00:22:47.520 --> 00:22:48.440 It's red right there. 00:22:48.440 --> 00:22:49.080 And it's really tall. 00:22:49.080 --> 00:22:49.980 Let's go figure that out. 00:22:49.980 --> 00:22:50.220 Yeah. 00:22:50.220 --> 00:22:52.960 And the web one, the logo is awesome. 00:22:52.960 --> 00:22:53.740 It's good. 00:22:53.740 --> 00:22:55.120 It is really good. 00:22:55.120 --> 00:22:55.420 Yeah. 00:22:55.420 --> 00:22:56.860 It's like a 70s thing. 00:22:56.860 --> 00:22:58.440 It reminds me of Austin Powers. 00:22:58.440 --> 00:22:59.320 Yeah. 00:22:59.320 --> 00:23:00.420 A little bit, right? 00:23:00.420 --> 00:23:01.080 Yeah. 00:23:01.080 --> 00:23:01.380 Yeah. 00:23:01.380 --> 00:23:04.180 In a non-copyright infringing way. 00:23:04.180 --> 00:23:06.680 Anyway, that's it. 00:23:06.680 --> 00:23:09.860 If people are looking for a profiler, Austin looks pretty cool. 00:23:09.860 --> 00:23:10.880 Check it out. 00:23:10.880 --> 00:23:11.520 Definitely. 00:23:11.520 --> 00:23:13.440 It seems like it's definitely one of the contenders. 00:23:13.940 --> 00:23:14.820 Anthony for sending that in. 00:23:14.820 --> 00:23:15.980 I want to talk about numbers. 00:23:15.980 --> 00:23:17.640 Does this fit in the screen? 00:23:17.640 --> 00:23:17.980 Oh, yeah. 00:23:17.980 --> 00:23:20.740 You got your mathematician hat on now or your wizard hat. 00:23:20.740 --> 00:23:21.460 I can't decide. 00:23:21.460 --> 00:23:23.320 I got this from a man. 00:23:23.320 --> 00:23:24.880 He writes two great stuff. 00:23:24.880 --> 00:23:26.140 First name Mosh. 00:23:26.140 --> 00:23:27.400 Is the last name Zadka? 00:23:27.400 --> 00:23:27.900 Zadka? 00:23:27.900 --> 00:23:30.660 Mosh, you got to contact me and find out. 00:23:30.660 --> 00:23:31.900 Tell me how to pronounce your name. 00:23:32.560 --> 00:23:33.980 But numbers in Python. 00:23:33.980 --> 00:23:35.180 Really great article. 00:23:35.180 --> 00:23:37.860 In Python, you don't really have to think about numbers too much. 00:23:37.860 --> 00:23:38.880 They just sort of work. 00:23:38.880 --> 00:23:39.140 Yeah. 00:23:39.140 --> 00:23:41.160 But you do kind of need to think about them. 00:23:41.160 --> 00:23:45.960 And this article is a really good, quick tutorial about the different things that you need to know. 00:23:45.960 --> 00:23:48.920 Like integers, they turn into floats really easily. 00:23:48.920 --> 00:23:52.780 Like any time there's a division, it'll turn into a float. 00:23:52.940 --> 00:23:57.580 Right, which is unlike other languages, which are like truncating sort of things, right? 00:23:57.580 --> 00:24:00.960 That basically take the floor of whatever the result would be. 00:24:00.960 --> 00:24:01.340 Yeah. 00:24:01.340 --> 00:24:04.820 In earlier Python versions, 2.7 like that. 00:24:04.820 --> 00:24:05.140 Yeah. 00:24:05.140 --> 00:24:05.480 Yeah. 00:24:05.480 --> 00:24:06.780 Like truncated off. 00:24:06.780 --> 00:24:07.440 Right. 00:24:07.440 --> 00:24:11.000 If you want that old type, now you got to double divide, like the two slashes. 00:24:11.000 --> 00:24:11.540 Yeah. 00:24:11.540 --> 00:24:13.680 And I forget about the two slashes thing. 00:24:13.680 --> 00:24:13.880 Yeah. 00:24:13.880 --> 00:24:15.860 I never use the two slashes because that seems wrong. 00:24:15.860 --> 00:24:20.840 Anyway, so the implications are weird though. 00:24:20.840 --> 00:24:24.360 And the other thing, okay, so you got integers, they turn into floats if you divide them. 00:24:24.360 --> 00:24:27.560 You got floats, which are things with decimal points in them. 00:24:27.560 --> 00:24:30.040 They're not the only things with decimal points in them though. 00:24:30.040 --> 00:24:36.260 One of the things you learn early on in programming, but some people are new to programming or numbers, 00:24:36.260 --> 00:24:41.200 so it's a good thing to remember, is floats don't behave like floating point numbers in math. 00:24:41.200 --> 00:24:44.880 Like the subtraction and addition are not inverses. 00:24:44.880 --> 00:24:47.600 And addition is not associative always. 00:24:47.960 --> 00:24:51.160 And you can't multiply and then divide and get the same number. 00:24:51.160 --> 00:24:53.560 Those are weird things you should be aware of. 00:24:53.560 --> 00:25:02.020 The normal thing that I mostly need to remember is don't try to compare floating point numbers with the double equals. 00:25:02.020 --> 00:25:04.700 You have to use something like approximate or something. 00:25:04.860 --> 00:25:05.040 Yeah. 00:25:05.040 --> 00:25:07.180 That's the one that can really catch people out. 00:25:07.180 --> 00:25:13.300 I mean, okay, so I thought I was going to get 14 and I got 13.9999999978. 00:25:13.300 --> 00:25:14.520 Okay. 00:25:14.520 --> 00:25:16.220 Well, it's computers. 00:25:16.220 --> 00:25:19.660 We know that stuff's truncated, but it's really easy to go. 00:25:19.660 --> 00:25:25.020 If X equal equals some number I'm looking for and that never ever happens. 00:25:25.020 --> 00:25:25.360 Right. 00:25:25.420 --> 00:25:28.480 It looks right and it is so wrong. 00:25:28.480 --> 00:25:36.440 And I think just our training for so many years in theoretical mathematics means that it's hard to look at that and go, that's wrong. 00:25:36.440 --> 00:25:37.880 Yeah. 00:25:37.980 --> 00:25:46.780 Well, it's interesting that when you see it in numbers, you can, like, for instance, one of the examples is one plus two minus two minus one is zero. 00:25:46.780 --> 00:25:47.740 Obviously. 00:25:47.740 --> 00:25:48.500 Of course it is. 00:25:48.500 --> 00:25:50.500 If it's floating point numbers, though. 00:25:50.500 --> 00:25:53.180 So floats don't end up with zero. 00:25:53.180 --> 00:25:56.340 You end up with a very small number, but it's not zero. 00:25:56.340 --> 00:25:57.280 Okay. 00:25:57.280 --> 00:25:58.200 So floats are weird. 00:25:58.200 --> 00:25:58.800 Be careful. 00:25:58.800 --> 00:25:59.820 Fractions. 00:25:59.820 --> 00:26:02.060 So if you don't use floats, there's fractions. 00:26:02.060 --> 00:26:03.440 Python has built in fractions. 00:26:03.440 --> 00:26:06.040 I actually have never really used these. 00:26:06.040 --> 00:26:06.660 It's neat. 00:26:06.660 --> 00:26:07.140 They're there. 00:26:07.140 --> 00:26:07.680 They're there. 00:26:07.680 --> 00:26:09.020 I've never used them either. 00:26:09.020 --> 00:26:15.520 But yeah, there's like a class called fraction with a numerator and a denominator or takes another fraction or a floating point. 00:26:15.520 --> 00:26:16.300 Yes. 00:26:16.300 --> 00:26:17.100 Even takes a string. 00:26:17.100 --> 00:26:18.120 How about that? 00:26:18.120 --> 00:26:25.220 The warning in this article is they, fractions take a lot longer than you expect they would for algorithms. 00:26:25.220 --> 00:26:28.340 So you can represent things as fractions. 00:26:28.340 --> 00:26:29.820 It's cool that you can do that. 00:26:29.820 --> 00:26:37.680 Be very careful with any sort of algorithm because it can explode in memory and size and time and stuff like that. 00:26:37.680 --> 00:26:39.220 So probably use floating point. 00:26:39.220 --> 00:26:45.960 That doesn't surprise me because when I have to do like fraction algorithms, in my mind, it takes a lot longer too. 00:26:46.640 --> 00:26:47.200 Yeah. 00:26:47.200 --> 00:26:54.420 The last one that he talks about, and it's something that some people don't realize right away, is that decimals are built in. 00:26:54.420 --> 00:26:58.760 So there's a decimals library that it's probably not surprising. 00:26:58.760 --> 00:27:01.340 One of the reasons it's in there is for financial transactions. 00:27:01.340 --> 00:27:05.140 They're set up to be correct with precision and do the right thing. 00:27:05.440 --> 00:27:06.900 And so I'm really glad it's there. 00:27:06.900 --> 00:27:11.260 Otherwise, we'd have like competing decimal third-party libraries or something like that. 00:27:11.260 --> 00:27:11.900 And we probably do. 00:27:11.900 --> 00:27:13.820 But this one's built in. 00:27:13.820 --> 00:27:30.780 I'm glad the article was written, though, because something weird about decimals that I didn't know about was there's a global state variable called context that holds the precision that's being used for decimal division and stuff. 00:27:30.780 --> 00:27:35.000 It could be anywhere in your program that the precision gets changed. 00:27:35.000 --> 00:27:39.240 So the recommendation in this article is to use a local context. 00:27:39.240 --> 00:27:43.720 So you can do one of those blocks, context, what are those things called? 00:27:43.720 --> 00:27:45.360 Context manager. 00:27:45.360 --> 00:27:47.040 Context manager, yep. 00:27:47.040 --> 00:27:54.600 You can use the context manager, local context, to set a local context precision for your arithmetic. 00:27:54.600 --> 00:27:55.780 So that's good. 00:27:55.780 --> 00:27:58.200 That seems like that should be the required way. 00:27:58.340 --> 00:28:03.420 Because just setting it globally seems really, I don't know, it seems wrong. 00:28:03.420 --> 00:28:06.640 Because, you know, think of the race condition there. 00:28:06.640 --> 00:28:11.900 I was doing math, and then the precision got cut in half, and then it wasn't what I expected anymore. 00:28:11.900 --> 00:28:13.980 Yeah. 00:28:13.980 --> 00:28:17.020 Or, I don't know, maybe there should be a minimum precision. 00:28:17.020 --> 00:28:18.080 This is interesting, though. 00:28:18.080 --> 00:28:21.720 Like, I didn't realize that you could even change the precision of decimals. 00:28:21.960 --> 00:28:34.680 So, like, in the docs it says, unlike hardware-based binary floating point numbers, the decimal module has a user-alterable precision defaulting to 28 places, which can be as large as needed for a given problem. 00:28:34.680 --> 00:28:36.060 So, yeah, you can change it. 00:28:36.060 --> 00:28:47.940 The example in the Python document on the docs show, just globally changing it halfway through a calculation, which seems like a bad, let's kick them down the stairs instead of teaching them to hold on to the handrailing. 00:28:48.080 --> 00:28:53.380 But this is really cool, like, this local context, change it, you can set it really high. 00:28:53.380 --> 00:28:54.080 That's cool. 00:28:54.080 --> 00:28:57.740 I had no idea that you could actually change that to grow as you need it, which is cool. 00:28:57.740 --> 00:29:07.680 Yeah, I guess you could still use the global context as long as you, maybe this isn't safe, but as long as you always remember to set it before you do decimal arithmetic. 00:29:07.980 --> 00:29:09.560 It's safe as long as you're not doing threading. 00:29:09.560 --> 00:29:10.460 Oh, yeah. 00:29:10.460 --> 00:29:11.220 Okay. 00:29:11.220 --> 00:29:14.900 Yeah, because what if somebody, some other thread has the same idea and changes it? 00:29:14.900 --> 00:29:21.000 I think the idea is maybe, it seems to me like possibly it would be better if once set, it couldn't be set again. 00:29:21.000 --> 00:29:25.340 Like, you could set it at the beginning of your program, but it couldn't be altered and altered and altered. 00:29:25.340 --> 00:29:25.720 Yeah. 00:29:25.720 --> 00:29:32.800 Like, right, something along those lines, like, okay, we set it, we're done, it's an exception if you try to set it again to something else and so on. 00:29:32.860 --> 00:29:34.640 I mean, it probably is a convenience. 00:29:34.640 --> 00:29:37.160 Yeah, this is the whole world I didn't even know about. 00:29:37.160 --> 00:29:37.760 This is cool. 00:29:37.760 --> 00:29:43.580 Yeah, I would probably set up some sort of, like, hook or something to make sure that you're only setting it one place if you're doing that. 00:29:43.580 --> 00:29:44.200 Yeah. 00:29:44.200 --> 00:29:44.440 I don't know. 00:29:44.440 --> 00:29:45.720 Yeah, sounds good to me. 00:29:45.720 --> 00:29:46.780 Cool. 00:29:46.780 --> 00:29:51.940 Anyway, yeah, this is actually more interesting than I thought because, like, as usual, I've learned something, which is cool. 00:29:51.940 --> 00:29:57.820 Last thing on this, we're going to link to the standard library documentation for fractions and decimals because you may not have heard of them. 00:29:57.980 --> 00:30:05.060 And then a very old article that if you really care about floating point numbers, you should at least know this article exists. 00:30:05.060 --> 00:30:08.380 Although I don't think I've actually gotten through the whole thing ever. 00:30:08.380 --> 00:30:12.380 But it's what every computer scientist should know about floating point arithmetic. 00:30:12.380 --> 00:30:13.900 That's a good article. 00:30:13.900 --> 00:30:14.500 Yeah, cool. 00:30:14.500 --> 00:30:15.020 All right. 00:30:15.020 --> 00:30:17.360 Any extras for us today, Michael? 00:30:17.360 --> 00:30:18.580 You know, not too much. 00:30:18.580 --> 00:30:21.080 I don't have too much to share right now. 00:30:21.080 --> 00:30:21.880 Nothing personal. 00:30:21.880 --> 00:30:29.520 But I do want to say thank you to everyone who subscribed to the YouTube feed of this podcast because we're breaking every segment. 00:30:29.520 --> 00:30:30.820 We've just covered six things. 00:30:30.820 --> 00:30:32.880 We're breaking that into six different videos. 00:30:32.880 --> 00:30:35.880 And you can see us on video, which is kind of cool. 00:30:35.880 --> 00:30:39.120 A bunch of people are subscribing at pythonbytes.fm/YouTube. 00:30:39.120 --> 00:30:40.360 You all can check that out. 00:30:40.360 --> 00:30:43.520 And you will see that Brian has awesome hats for every segment. 00:30:43.520 --> 00:30:45.780 Well, at least this episode. 00:30:45.780 --> 00:30:46.860 This episode. 00:30:46.860 --> 00:30:48.560 Which, yeah, you got to wait. 00:30:48.560 --> 00:30:49.220 Yeah, for sure. 00:30:49.220 --> 00:30:49.860 This episode. 00:30:49.860 --> 00:30:52.100 So eventually, you'll get to see the hats. 00:30:52.100 --> 00:30:52.460 Okay. 00:30:52.460 --> 00:30:53.840 I'm glad we mentioned that. 00:30:53.840 --> 00:31:03.300 I wanted to mention also that Python 3.9.0 alpha 6 is the last alpha release before we go into betas, I believe. 00:31:03.300 --> 00:31:05.200 And it is available. 00:31:05.200 --> 00:31:10.920 And it has the peg parser that we talked with, I think, last week about a little bit. 00:31:10.920 --> 00:31:11.340 Yeah. 00:31:11.340 --> 00:31:11.500 Yeah. 00:31:11.500 --> 00:31:13.580 We was here and talked about that was really cool. 00:31:13.580 --> 00:31:14.600 The work he's been doing there. 00:31:14.600 --> 00:31:18.080 That's a big long-term upgrade, right? 00:31:18.080 --> 00:31:21.740 That's something that got written in the original version of Python. 00:31:21.740 --> 00:31:24.480 It was unchanged and obviously can be better, right? 00:31:24.480 --> 00:31:29.220 Basically, the syntax was limited by the parser and how much it looked ahead and stuff. 00:31:29.220 --> 00:31:35.740 And so this should open up the language for more complex concepts or make it easier to add concepts to it. 00:31:35.740 --> 00:31:35.920 Yeah. 00:31:36.020 --> 00:31:36.300 All right. 00:31:36.300 --> 00:31:38.120 So I see we have some competing jokes here. 00:31:38.120 --> 00:31:39.060 You want to go first? 00:31:39.060 --> 00:31:39.660 Yeah. 00:31:39.660 --> 00:31:42.480 I just put a call out on Twitter and said I need some more jokes. 00:31:42.480 --> 00:31:45.420 And boy, I got a whole bunch of great ones back. 00:31:45.420 --> 00:31:46.340 I'm going to pick one. 00:31:46.340 --> 00:31:47.640 This one's from James Zabel. 00:31:48.000 --> 00:31:55.060 If you put 1,000 monkeys at 1,000 computers, eventually one will write a Python program and the rest will write Perl. 00:31:55.060 --> 00:31:56.900 That's right. 00:31:56.900 --> 00:32:00.320 I think maybe like 950 of them will write Perl. 00:32:00.320 --> 00:32:03.860 A couple of them are just going to be writing regular expressions like all on their own. 00:32:03.860 --> 00:32:04.920 Yeah. 00:32:04.920 --> 00:32:05.920 That's true. 00:32:05.920 --> 00:32:07.280 All right. 00:32:07.300 --> 00:32:09.300 I have one that's maybe in a similar vein here. 00:32:09.300 --> 00:32:11.800 So, you know, like we talked about Austin. 00:32:11.800 --> 00:32:14.680 It has all these different user interfaces and it's very user friendly. 00:32:14.680 --> 00:32:19.060 Well, you could say that Unix is very user friendly as well. 00:32:19.060 --> 00:32:22.160 It's just very particular about who its friends are. 00:32:22.160 --> 00:32:25.020 Yeah. 00:32:25.020 --> 00:32:26.200 I got friends like that. 00:32:26.200 --> 00:32:26.560 Yeah. 00:32:26.560 --> 00:32:29.340 I got that one from the Pyjoke package. 00:32:29.340 --> 00:32:31.720 So pip install Pyjoke and you can have it too. 00:32:31.720 --> 00:32:32.060 Yeah. 00:32:32.060 --> 00:32:32.700 That's good. 00:32:32.700 --> 00:32:33.680 Yeah. 00:32:33.680 --> 00:32:34.100 Anyway. 00:32:34.100 --> 00:32:34.460 Cool. 00:32:34.460 --> 00:32:34.960 Thanks. 00:32:34.960 --> 00:32:35.380 All right. 00:32:35.380 --> 00:32:36.000 Fun as always. 00:32:36.840 --> 00:32:37.740 Great to be here with you. 00:32:37.740 --> 00:32:37.940 Bye. 00:32:37.940 --> 00:32:38.260 Bye. 00:32:38.260 --> 00:32:40.140 Thank you for listening to Python Bytes. 00:32:40.140 --> 00:32:42.600 Follow the show on Twitter at Python Bytes. 00:32:42.600 --> 00:32:45.640 That's Python Bytes as in B-Y-T-E-S. 00:32:45.640 --> 00:32:48.520 And get the full show notes at Python Bytes.fm. 00:32:48.520 --> 00:32:53.600 If you have a news item you want featured, just visit Python Bytes.fm and send it our way. 00:32:53.600 --> 00:32:55.640 We're always on the lookout for sharing something cool. 00:32:55.640 --> 00:32:58.820 This is Brian Okken and on behalf of myself and Michael Kennedy, 00:32:58.820 --> 00:33:02.120 thank you for listening and sharing this podcast with your friends and colleagues.