[MUSIC] So, hopefully this gets you started
with Python, the programming language with the iPython Notebook, and
a little bit of iterating the console. We're gonna be using this console
again and again, it's really a fun, simple way to manage and
interact with data. And there's also tools for
visualizing, for navigating, for doing machine learning
in this Python space. So, it's really a great
programming language for us. And, in fact,
there's been a lot of surveys that say most recently Python is the
programming language for data science and that's why we picked it for this course. As a final step, let's talk about
creating functions in Python. It's actually pretty easy to create a wide
range of functions within Python and it's pretty natural. So there's two ways of doing it. So let's go ahead and get started. So, again ask m for a text box and we're gonna talk about creating functions in Python. Okay, so
the first way is using the def command. So this is defining a function,
let's say a fun function, add 2 which takes an element x and
adds 2 to it. So we write def add2, and in parenthesis,
you put the number of parameters you have, there is this x, you could have x,
y, z, and so on. And then you put a colon at the end. And just like with flukes,
we want to align in vertically, kinda tabulated, until we've written
out all the function we want to do. So for example,
we could say y is equal to x plus 2, and then we say return y. So here we defined a function add 2. So let's, remember integer value i,
let's just set it to some number, let's say we say that i is equal to 5,
and we say add 2 with the input i and we get 7. Voila. The second way to define functions is
using what Python calls lambda's, and these are for simple functions and
it's useful to know it. It's used in a variety of places where
you just do a simple transformation, even add to is a simple transformation so
for example, let's create a function called square. So this is the square function, which is a lambda that takes into
input x and returns x times x. So if I read this to you when defining
a function, this land is a function, takes x's input and returns x times x. That's what it tells us after the column. So we defined that and now we can
apply square to anything we want, so for example. If we say what is the square of 3,
it should say 9 and there we go,
two ways to define functions in Python. Now we have the grasps of Python's basics,
they can used for all assignments we're gonna be
building up in this first course. [MUSIC]