And to start with Python, first start the Python
Shell. So if you don't know how to start it,
please go back to the introduction section where
you can see the lesson on how to install Python,
on Windows, on Linux, and on MAC OS, and then come
back here for the explanations. So this is the
Python Shell. And the first thing you can see here
is the Python version you have here. So I have
version 3, Python 3.9. But just the important
thing is that you have Python 3, okay. And
then you're going to see three brackets, three
angled brackets, and that's where you're going to
type some Python instructions. So we will see
later that you can create complete files with lots
of lines of code, which are basically all
instructions that are going to be executed. And
with the Python Shell, instead, you don't write a
complete file, you just write one instruction at a
time, and when you press enter, the instruction is
going to be executed. And in addition to that, the
results of the instruction will also be evaluated
and printed directly on the Shell. So let's just
type anything, let's just type number 3, and
press enter, and you can see now I have here 3.
So that was the instruction, which is just a
number for now. So it doesn't do anything. But you
can see we have the instruction, which is
evaluated, so of course three is evaluated to
3 and is printed here. I can also do
hello world, like this. So use double quotes for
now. Okay, hello world, I press enter, and you
can see hello world. So here you have your first
hello world program in Python. And in this section,
we're going to continue with this Python Shell to
discover variables etc. And so you can just type
literal value like this, and you can also for
example, use Python functions. So there is one
Python function, which is named len for length.
And you have to open and close parentheses and
need to give, for example, a string of characters
like this after this. So if I just type hello,
world like this, here, I press enter. And this as
you can see, this gives us 11. Okay, because this
Python function, which is in the core module in
the core Python module, is going to compute the
length of the string here which is 11. So we have
11 characters, including the space. Okay, and
don't worry about this. We are going to come back
to that just later. Hey, it is just to show you
so what you can do with the Python Shell. So you
can write instructions, you press enter, okay, you
can press enter as you can see here, I press enter
and whatever is here will be executed and also
evaluated and printed here.