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So, hopefully this gets you started
with Python, the programming language

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with the iPython Notebook, and
a little bit of iterating the console.

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We're gonna be using this console
again and again, it's really a fun,

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simple way to manage and
interact with data.

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And there's also tools for
visualizing, for navigating, for

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doing machine learning
in this Python space.

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So, it's really a great
programming language for us.

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And, in fact,
there's been a lot of surveys

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that say most recently Python is the
programming language for data science and

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that's why we picked it for this course.

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As a final step, let's talk about
creating functions in Python.

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It's actually pretty easy to create a wide
range of functions within Python and

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it's pretty natural.

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So there's two ways of doing it.

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So let's go ahead and get started.

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So, again ask m for a text box and

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we're gonna talk about

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creating functions in Python.

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Okay, so
the first way is using the def command.

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So this is defining a function,
let's say a fun function,

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add 2 which takes an element x and
adds 2 to it.

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So we write def add2, and in parenthesis,
you put the number of parameters you have,

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there is this x, you could have x,
y, z, and so on.

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And then you put a colon at the end.

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And just like with flukes,
we want to align in vertically,

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kinda tabulated, until we've written
out all the function we want to do.

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So for example,
we could say y is equal to x

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plus 2, and then we say return y.

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So here we defined a function add 2.

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So let's, remember integer value i,
let's just set it to some number,

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let's say we say that i is equal to 5,
and we say

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add 2 with the input i and we get 7.

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Voila.

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The second way to define functions is
using what Python calls lambda's, and

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these are for simple functions and
it's useful to know it.

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It's used in a variety of places where
you just do a simple transformation,

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even add to is a simple transformation so
for example,

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let's create a function called square.

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So this is the square function,

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which is a lambda that takes into
input x and returns x times x.

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So if I read this to you when defining
a function, this land is a function,

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takes x's input and returns x times x.

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That's what it tells us after the column.

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So we defined that and now we can
apply square to anything we want, so

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for example.

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If we say what is the square of 3,
it should say 9 and

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there we go,
two ways to define functions in Python.

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Now we have the grasps of Python's basics,
they can used for

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all assignments we're gonna be
building up in this first course.

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