Matplotlib Tutorial 1 - Introduction and Line

Key Takeaways

What is going on everyone? Welcome to a data visualization with Python and Mattplot lib tutorial series. I'm going to be redoing this series. I have an older version of this series on this channel, but it was actually one of the first series I ever did and it could stand to be updated quite a bit, especially as that we get into the more advanced aspects of using Mattplot lib. So, here we go. We're going to go ahead and update this series. is I'm not going to release this series like I normally do, uh, where I do like one video a day. I'll be releasing this series in rather large chunks at a time. And the reason for that is the series doesn't really have to be followed linearly. The first few introductory tutorials, you if you're not familiar with Mattplot Lib, you probably should follow along linearly. Uh, but then from there, you should be able to make your choice into kind of what kind of topics that you're specifically interested in. By that same token, a lot of times I release the series first and then I go back and put put the, you know, text versions of the tutorials on pythonprogramming.net. Uh, and and this time I'm planning to have everything released all together. So, you should be able to get the source code and the videos at the exact same time and then you can go to pythonprogramming.net and kind of figure out which of the main topics you're mostly interested in, what you're looking for and all that. So anyways, in this series, we're going to cover everything just, you know, from the the basics of graphing graphs with Matt Plow lib, you know, your typical scattered plots and line graphs and bar charts, stuff like that. And then we'll get into a bunch of the customization options, things like plotting date time, doing fills, having multiple plots on the same figure and sharing axes, all kinds of stuff like that. We'll talk about basemap and we'll talk about a little bit of live graphs and then we'll talk about 3D graphing and then that will pretty much round out the the series. So feel free to bounce around if you don't know the basics. Kind of stick around for the basics, but otherwise you should be able to kind of bounce around. Some stuff we'll we'll reference like we'll teach legends and then I'll show you how to customize legends and then later on we may actually customize legends based on a legends tutorial. So for that reason you might want to follow linearly but you shouldn't have to. So anyways first things first how do we get mapplot libs? So there's you know a few different ways that we can go about actually acquiring uh mapplot libs. So the first way would be via your command prompt. Okay. So cmd.exe you should be able to go there and uh let's open up that. And if you have Python 3 or a new version of Python 2, this tutorial is going to be doing Python 3 and using Python 3, but feel free to use Python 2 if you want. Just understand there's some changes you'll have to make, and I'm not really going to uh touch on those. So, first of all, the easiest way is if you have a 32-bit version of Python, which you do have if uh if you just installed like the default, it doesn't matter what your operating system is. You might have a 64-bit version of Windows unless you tried to. you have 32-bit Python. If you want to check, you can always just type in, you know, Python and read at the very top here. See, my Python is 64-bit. But if yours says maybe 32bit, then you have 32-bit. So, uh, just do quit here. So, to get mapplotib, the easiest thing to do is pip install mapplot lib and that should be it. If it says pip is not a recognized command, then you'll have to give the full path. So, on Windows, that would be CL if you have, you know, for Python and then the version. I'm using 3.4. So we would say python 34 slashscripts slashpipin install and then mapplot lib. Okay. Uh that should be good enough. Uh later on you might find that it says you don't have a module and there's like a few of them like um let's say six. Six comes up a lot. People go import mapplot lib and it says no module named six. Well you have to get six too. anytime it Python says hey you don't have this module uh you need to get it this is how you would get it same way you got mapplot lib so go pip install six okay and that would give you six so that's with the command prompt uh next we could use uh let's go up here let me pull over a new tab and you can go to mapplotib.org mapplotib.org For some reason whenever I go to mattplotive.org I get a lot of times like this website like it's like it's down all the time. I don't know what the deal is there. But anyway, you can come to mattplotlib.org. Scroll down to downloads. We'll click on the mattplotibs downloads page. And then here you get the downloads for 64-bit and 32-bit Windows. You can also get the wheels. You can install files with wheels. Uh but if you're on Windows, just get this or this. Right. Win32 would be for 32-bit. Win 64 or Win AMD 64 for uh 64-bit. There's your OSX images and uh Linux you would just install via the source. So once you have Mattplot lib, you should be able to um import Mattplot Lib without a problem. So the next thing that we're going to go ahead and do is just show a really simple line graph with Mattplot Lib. So to do that and to use mapplot lib the first thing we need to do is import the mapplot lib but uh more specifically what we use is piplot and piplot is the main kind of functionality that you're going to be using all the time you're pretty much every application I can't think of one that is not going to be using piplot so you're going to do this a lot so you're going to need this import mattplot libpipplot as PLT. We do that just to shorten it and that's a standard. So most people shorten piplot as plt. So if you're looking at other people's code, uh you can kind of you'll understand that. You won't have to usually trace that back to their imports. You'll just know plt. It's kind of like with numpy, people import numpy as np. Everyone does that. So it's a good idea to do that too so people can understand your code when you need help. So uh import mapplotib.pipplot as plt. And that's fine. The next thing that we're going to go ahead and do is um is plot. So when we go to plot, we invoke the piplot module which we say is plt. And then we say dot and plot. And when you go to plot, you plot x's and you plot y's. Now we don't really have anything for x and for y. So uh let's fill those in. Let's just create two lists. So we'll say x is 1 2 3. And then y you can pretty much say whatever you want. We could say five not 76 57 let's do four. Okay. So our graph does something interesting I guess. Okay. So we plot there and then now what happens with graphics is everything is drawn to a background first and then when everything's all ready to be shown that's when we bring forward whatever's been you know we've been working on in the background. Mattplot Lib is no different. So in the background, this graph has been drawn, but we need to bring it to the forefront. So the way that we do that is just with a simple plt.show empty parameters. And that's it. So now we can save and run this. And I suppose we wait for a moment. There we go. And there is our graph. So we'll be talking a little bit more about how this works. Uh but basically, you know, you've got this graph. It's a line. And you've got like this kind of like gooey window that you have. Uh, and then you got these buttons down here. So, we can run through those buttons real quick. First of all, you can resize the graph, no problem. You should be able to move that around a lot. Then you've got these first three buttons. We can't really do anything with them just yet. So, we'll talk about those at the end. We'll start with this little cross here. If you click that, you can now click on your graph, click and hold, and like drag the graph around a little bit. Okay. So, that's one thing. Then you've got like the zoom. So you can zoom into a specific area if you wanted. You can also zoom out. So that was with a left click and hold to draw the the uh triangle. You can do the same thing by right click and hold. And this instead will zoom out. So we're able to zoom out that way. Um then you've got configure subplots. Right now this doesn't really mean much to us, but we can move a few things. Like you'll notice there's a lot of empty space on the left, the right, the bottom, and the top. we can kind of we can uh use this to adjust that space and later on we'll use it because you can actually program program in these values to change them. Uh so we'll talk about that when uh that comes up. Then you have this save the figure. This is just so you can actually save the image or even a vector of the graph and a bunch of other options too. Then we go back to uh these buttons. So first you've got this little home that'll return you to the original view. So you could click that and now you're at the original view. Everything's back to normal. You can use the back to previous view to go back one. You can keep hitting this and keep going back. Conversely, you can go forward, right, and go back to the original views before that. So those are the basics of mapplot lib. Hopefully you guys are up to this point. If you have any questions or comments, please feel free to leave them below. Otherwise, as always, thanks for watching. Thanks for all the support and subscriptions and until the next