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Instructor: Welcome back.

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We just learned what a programming language is.

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It's just set of instructions that we give to a translator

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and this translator can be an interpreter or a compiler.

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And we give these files that we create our own code,

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our source code, to these translators

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and they allow us to give instructions

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to machines, to computers, to phones.

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So we learned that we need these machines

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in order for us to write Python, right?

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How can we get these?

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Well, we download them, and here we download Python

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from the Python Software Foundation from python.org.

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Now, before we download Python,

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we're gonna wait a little bit because in this course,

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I want you to understand why we're doing things,

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not just follow my tutorials, follow my videos

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and well, not understand the meaning

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and the fundamentals behind why we're doing things.

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You should be able to teach what you're going to learn.

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So let's take a pause here for a second.

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If this is the first time

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that you're learning a programming language,

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I have some good news for you.

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At the end of the day,

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all programming languages do the same thing.

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They tell the machine what to do.

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However, different languages have different ways

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of doing it.

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The beauty is that most languages

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have very similar principles.

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If this is your first programming language, well,

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this is gonna be the hardest part,

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learning the first one.

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Afterwards, every new language you learn

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becomes easier and easier

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in the sense that it's not the same as, let's say,

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learning English and Japanese,

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two very distinct languages.

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In programming, things become a lot easier

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as you learn that first foundational language.

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Now, if this is not your first language

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and let's say you've written code in C, C++ or JavaScript,

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and you just wanna learn Python, well,

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you're gonna find these first couple of videos quite easy.

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But bear with me, trust me, we're gonna get

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into some advanced topics here

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and we're gonna make you a full-fledged developer

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by the end of this.

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But let's go back to this topic at hand, this idea

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of downloading this translator.

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The thing is, when people refer to Python, the language,

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they're most likely talking about the implementation.

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That is, they're talking not about the language itself

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because Python, the language is just a specification.

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You can think of it as a document that somebody wrote

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that says, "Hey, when I write the words def,

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that means something in Python.

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And when I write something like print,

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that means something in Python."

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But the translation machines, well, we can have tons

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of them, different interpreters, different compilers.

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For example, python.org,

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when you click download here,

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you're actually downloading this, the CPython

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because it's written in the C programming language.

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This is what you're downloading.

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It's a program written in C to read your Python file

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and well, run it on a machine.

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But there's other implementations.

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For example, there's the Jython Project

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and this is a translator that is written

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in the Java language.

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There's pypy, which is actually written in Python.

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So it's a interpreter,

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it's a translation machine written in Python.

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And then there's also things like IronPython,

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which is written for the .NET framework.

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So here's a little trick question.

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When you download from Python,

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the official language is actually CPython.

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You're downloading this interpreter

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that follows the Python specification,

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but at the end of the day,

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it's a machine built by somebody.

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But these machines can well, come in many forms.

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So when most people talk about Python,

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they're talking about this one, CPython

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that well, does our translation for us.

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It interprets our Python code and runs it on our machine.

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So we're downloading this, and if you wanna really get

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into details as to what we're downloading,

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well, we're downloading a machine

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that takes our Python code, which don't worry,

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we're going to write

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and it goes through the interpreter,

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which we download using CPython.

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And this CPython is going to create something

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called a bytecode.

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For example, this bytecode prints Hello, World

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on our screen.

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Now, this might look like gibberish to you,

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and even for me, I don't know bytecode.

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This looks pretty well, confusing

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just for printing Hello, World to the screen.

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Well, the interpreter does that automatically for us.

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We don't see it, it's behind the scene.

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Now, once it creates a bytecode that is closer

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to machine code, it then uses the CPython virtual machine,

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again just something that runs this code

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and then this code gets run on our machine.

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Now, you're never ever going to be asked this question

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in an interview.

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I mean, maybe,

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and most developers don't know this

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but I want you to use this as a reference

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that when we write Python code throughout the rest

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of this course, this is what's happening.

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We're writing Python, it gets interpreted line by line

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and formed into what we call bytecode.

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And this bytecode gets run on the CPython virtual machine,

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which runs on our computers, our phones, our laptops

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and when we're downloading from python.org,

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we're downloading these two pieces

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so that once we have them downloaded, we can run Python.

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All right, that was a tough one, and I mean,

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we just got started.

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I hope your brain isn't exploding.

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Again, this is something for you to use as a reference.

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But you know what?

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I think it's time for us

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to learn how to actually run Python code.

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And don't worry, we are getting there.

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We are going to write our first Python program very soon.

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I'll see you in the next one.

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Bye-bye.