[MUSIC] >> Today we're going to talk about
two really exciting tools for programming machine learning algorithms,
and also useful in data science. One is the Python programming language,
and the other one is what's
called the iPython Notebook. At this point, I'll assume that you have
already installed Python in your system. You've gone through those
steps of installation. And now I'm just gonna go over
a few tips to get started. There's lots and lots of resources
available online for you to explore and familiarize yourself with all
the techniques that you need to do. But really, I think it would be fun for
us to go over this together, since this is a really,
really useful tool. And something that makes
a tremendous difference in practice. When you first call iPython Notebook,
you are faced with something like this. It's basically a version
of your directory, with all the files in the directory. There's some data files that I have,
as well as some iPython Notebooks I have created
earlier and some other data net file. This is more like a file browser. So what we're gonna do is
start a whole new notebook. So I am gonna go New, Python 2, since we're gonna have a notebook
that is a Python notebook. And welcome this is iPython notebook. This store is gonna run for a few years now and has really changed
how we build machine learning and data science algorithms and
how we communicate with others. It's a really useful tool. It blends two things that I love, Python, a simple scripting programming
language with Wiki pages, things which make it reasonably
easy to communicate with others. So, Python plus Wiki pages
is the iPython notebook. So today I'm gonna both show
you the iPython Notebook and also gonna show you some tips and
tricks in Python just to get started, assuming that you can program in Python or
in other programming languages. So you've run IPython Notebook and
you started a fresh new one. Let me just walk you over the interface. So at the very top here is
the title of the notebook. And we're going to change
it to something else. So I'm going to change
it to Getting Started with iPython Notebook. And there you go. We have a new notebook,
and that's the title. And so this notebook is kind
of like a console for Python. But also it allows you to save the pages
that you generate, and include text and images in that. And we're gonna play with all
of that during this course, because it's really useful. It has a menu here that
allows you to do things like save the file that you have and
load a new one, edit, copy, add new cells, and
we're gonna talk about those soon. But let's just get started. So let's get started with Python. I want to click on one of the cells, which
is kind of like an entry in a console. And I'm going to type my
first Python function. So the first function I'm
going to do is just print. So I'm going to print a string and
strings in Python can be single quotes or double quotes, is up to you. And the string I'm going to
print is the famous hello world. And when I press Shift-Enter,
it executes a cell so you have to remember to press Shift-Enter. We'll talk about pressing
just Enter in a second. And after executing, it says Hello World. So now,
let's take a ride on iPython Notebook and some of the Python functions that we're
interested in using during these courses. So the first piece of iPython Notebook
is that you can include text, and really well-formatted text, so
there's two ways of accessing text cells. So the first one is to
go over here to cell, cell type and call it markdown. And then you click on it and
you can start writing. And it's really a mark down
language kind of like Wikipages. So if I put a pound here,
I can do a header, #Getting started with Python. Oops.
And now instead of pressing Shift+Enter, we press regular Enter,
it gives you a multiline cell. So Enter. Let's get started with Python. And let's do a sub-header now. The first thing we're gonna assume
is what you have done so far. So we have done the following. So just press enter. Here's a list. We've done, we've installed Python, the Python programming language. We've started iPython Notebook. And okay. So that did not work so well. Okay.
I executed it, it's not quite right. Let me see what I forgot, so
I can double-click on it and edit. I forgot to put a space here. So Space between the different lines. So we install iPython, and we start the iPython Notebook,
this is what we have done so far. And now if I press Shift + Enter,
and you can see now we have a list. [MUSIC]