Introduction to Programming and Python

0:05Welcome, everyone.

0:07You're here today because you want

0:08to learn a little bit of something about programming.

0:11And I want to talk quite a bit about programming itself.

0:14The act of developing programs and applications

0:17for our computers.

0:18Now, you may have an idea of what programming

0:20is, you may have even done some programming and some scripting

0:23in the past, it's certainly a very common thing to have done.

0:25So you may have done that, but even if you haven't, this

0:28is a perfect place to start.

0:29I want to level set exactly what we're

0:31talking about when we talk about programming so that we're all

0:34approaching it from the same mindset, in the same direction.

0:37And we understand the vocabulary that we're using

0:39and why we're doing what we're doing

0:41and really just answer the question initially here,

0:43what the heck is programming?

0:44What in tarnation are we doing?

0:46And I think the answer to that question

0:48is actually relatively straightforward,

0:49although as always with computers,

0:51the devil is in the details.

0:53Programming is just the act of providing a set of instructions

0:57that the computer can run.

0:58The computer can execute-- is the term we often use.

1:01When a computer program runs, we say it's executing.

1:04And all we're doing is saying, hey

1:05computer, this is what I want you to do.

1:09Why is this important?

1:09Well, computers don't know what to do on their own.

1:12They need someone to tell them what

1:13they should be doing, how to respond to different user

1:15interactions, where to get data from,

1:16what to add up or subtract, or when to show the cool graphics.

1:20All of this stuff gets supplied to the computer

1:23by a programmer using something called a programming language.

1:26I think you've probably heard of some programming

1:28languages before in the past.

1:30A programming language is nothing more than a language

1:34that we can use to communicate those instructions

1:36to the computer very concisely and very clearly and very

1:40explicitly.

1:42Now I want to unpack this a little bit.

1:43Why do we need to use these programming languages?

1:46Why do we have to be so explicit and concise?

1:48And the answer to that question is

1:50because, well, one of my favorite phrases and this

1:52could probably be the mantra for this entire set of videos,

1:55computers are dumb.

1:57I know.

1:58You don't think they're dumb, right?

1:59Most people don't.

1:59They're like, computers are amazing.

2:01They can do all those crazy things

2:02I was just talking about it a moment ago, right?

2:04They can calculate pi out to 6,000 digits

2:07in the time it takes you to type in the letters p and i.

2:09They can play amazing graphical video games

2:12with all sorts of crazy physics going on.

2:14They can do an enormous number of things really, really well.

2:18But the simple fact of the matter

2:19is they can only do those things when

2:21they've been instructed to.

2:21Someone had to figure out how to do those first

2:23and tell the computer to do that.

2:25And a lot of those things aren't really all that complex

2:28when it gets right down to it.

2:29I mean sure it can calculate pi up to 6,000 digits.

2:32But so can I?

2:33It just takes me a lot longer.

2:34That means the computer is not necessarily smart.

2:37The computer is just fast.

2:38And that's what you need to understand.

2:40Computers are very, very fast, but they're also not

2:44very smart.

2:45Computers are dumb.

2:46And they don't handle things like ambiguity or uncertainty

2:50or contradictions very well at all.

2:52A computer needs things laid out very explicitly.

2:54A computer wants to know what it's supposed to do,

2:56when it's supposed to do it, and you

2:58need to be as direct and explicit as possible.

3:01If you give some ambiguous instructions to a computer,

3:04well, best case scenario the computer

3:06is going to interpret those instructions in a way

3:09that you did not intend and has some sort

3:10of unintentional consequences, it's

3:12not going to operate the way that you

3:13thought it would operate.

3:14Worst case scenario, it's going to crash.

3:16Right, the whole computer is going to come down.

3:18The system is going to stop.

3:19The operating system is going to stop.

3:20I think you've probably worked on

3:22a computer system in the past that has crashed,

3:24certainly not an uncommon operation, that's

3:25because the computer ran into some instructions

3:27and ran into some code that it didn't understand

3:30how to deal with or how to handle

3:32and it just threw up its hands in the air said,

3:33fine I don't know what to do with this.

3:35I'm just going to give up.

3:36So computers-- yes computers are dumb.

3:39I want you to remember that and keep that in mind.

3:41So how do we communicate instructions

3:43to a dumb computer.

3:45Well, you may be thinking, hey, I speak English.

3:47I can use English, right?

3:48I'm pretty great at communicating instructions

3:50say to my children when I want them to get dressed

3:52and put their shoes on and get ready for school.

3:54I mean I can 4-year-old how to get ready for school.

3:57Surely I can computer how to calculate the pi.

4:00Well, it's not as easy as all that.

4:01Right?

4:02The languages that we use to communicate with each other

4:04and to other people are called the natural languages.

4:07And this is because they have naturally

4:08evolved in the human species.

4:10We're talking about all the language

4:11that we speak English, Mandarin, Russian.

4:13Whatever language you talk, these

4:15are the natural languages.

4:16And natural languages are great at conveying

4:19all of the intricate complexity of human emotion

4:22in our inherent contradictions in all

4:25of these different ambiguous things.

4:26We use not just our language, but our hands,

4:28we use facial expressions.

4:30And all of this combines to make a really powerful communication

4:33platform for people.

4:35But computers don't really deal well with that.

4:37Computers can't read the emotion out of your eyebrows.

4:40Computers cannot understand what your hands moving

4:42in a particular way might mean or how that inflects what it is

4:45you're saying.

4:46No, computers need things very, very explicit.

4:49And I think you've probably run into this before as well.

4:52You've heard of binary right?

4:54Zeros and ones.

4:55Every instruction, every application,

4:57everything that runs on a computer

4:59is ultimately stored in binary and as a bunch of code that

5:03is made up of zeros and ones.

5:05And that is how computers interpret everything.

5:08Why is binary so powerful?

5:10Because binary is unambiguous.

5:12There is no room for ambiguity in binary.

5:14It's either a zero or a one.

5:16It's on or off.

5:16It's true or false.

5:17It's yes or no.

5:18It can't be halfway between true or false.

5:21You can have something that's halfway between 0

5:23and technically you've got 0.5, but the computer,

5:26it's binary code doesn't know how to deal with that.

5:28It's either one thing or the other thing,

5:30which is a very clear cut and very direct and very precise.

5:32And that's very important for computers to do their thing,

5:36for computers to operate.

5:38What's the problem here?

5:39Well, of course people cannot speak binary.

5:42So we think about the gap between these two

5:45things, the natural languages and the binary languages.

5:48Where do people come into play?

5:49I mean, after all, I can't write binary code

5:52and to be perfectly clear nobody does actually

5:54write binary code.

5:55That's not a thing that happens.

5:57Worst case scenario people write something

5:59known as machine language.

6:00But the simple fact of the matter

6:01is binary is too verbose.

6:03It's too long.

6:03It would take thousands of digits just

6:05to express a simple basic instruction like adding

6:08two numbers together.

6:09So we can't write binary.

6:11People cannot write in binary code.

6:13But if people can't write binary and computers

6:15can't understand English, what's the answer?

6:17What's the compromise?

6:19Well, the compromise is what we call a higher order programming

6:22language.

6:22And we are going to talk specifically

6:24in this set of videos about one of them

6:26Python, although there are many programming

6:29languages out there.

6:29I've got a few examples up here in the upper C-Sharp, Java,

6:33Perl, .NET.

6:33You may have heard of some of these, some of them

6:35may be new to you.

6:37There are quite literally hundreds of viable programming

6:39languages out there.

6:40We're going to choose Python for a number of reasons I'll

6:42talk about in another video.

6:44So a programming language like Python is a compromise.

6:47Is a compromise between these two extremes.

6:49Between the natural languages and the preciseness of binary.

6:53It's strict enough for computers.

6:55So we can very explicitly state what

6:57we want to state to the computer, what

6:59we want it to do.

7:00But it's relaxed enough that humans can both understand

7:02it as well as write the code.

7:04A programming language-- a code that you

7:06use to instruct the computer is going to look somewhat legible.

7:10Somewhat readable.

7:11It will look kind of similar to the English language

7:14in this case.

7:14It's going to follow largely the rules of the English language.

7:17We're going to read it top to bottom, individual lines

7:19get read left to right, you'll see words like if and then

7:23and loop that you recognize from the English language

7:26although they have very precise specific meanings.

7:28You'll also see some constructs that

7:29don't make any sense at all.

7:31You'll see colons and parentheses

7:32and curly braces all used in places where you would not

7:35expect them.

7:36So there's going to be a lot of structure and rigidity,

7:38and we're going to have a very limited vocabulary of things

7:41that we can say with our programming language.

7:43So it is not a full fledged natural language.

7:45You couldn't really use a programming language

7:47to communicate between two people.

7:48It compromises between those two.

7:50It comes up with a decent way to make language or code

7:54that humans can read and write but will also

7:56be able to be ultimately interpreted

7:58by computers as a collection of zeros and ones.

8:01So that is what programming is.

8:03And that is ultimately why we use programming languages

8:06to program our computers, because say it with me,

8:08computers are dumb.

8:10They need us to be very precise, very explicit in what

8:14we want them to do.

8:15If we give them ambiguous directions,

8:17if we create some uncertainty, who knows

8:18what's going to happen?

8:19We certainly don't, so we want to avoid that

8:21as much as humanly possible.

8:23I hope this has been informative for you

8:25and I'd like to thank you for viewing.

0:05You'd like to start writing some code.

0:08I don't blame you.

0:09I want to start writing code with you.

0:10We are so close.

0:11We're almost ready to go.

0:12But we do need to level set a little bit more.

0:15There is a thread, a loose angle,

0:18that I left a little bit open in my last video--

0:20a question that was unanswered.

0:22And if you didn't notice it, well, that's

0:23OK because I didn't explicitly ask the question.

0:25You would have had to been paying very close attention

0:28to pick up on it.

0:29But let's refresh.

0:30What did I talk about in my last video?

0:32Well, I talked about the fact that computers only

0:34use binary code.

0:36But we need to write in something like a programming

0:38language so that we can understand what we're writing.

0:41And then the computers can interpret it and execute it,

0:44what we meant.

0:45But if we're writing Python code and the computer

0:48needs 1's and 0's, binary code, there's a gap there.

0:51How does my Python code, or how does my C code,

0:54or how does my Java code get converted into binary?

0:57Well, the answer is a separate step,

0:59a process called compiling.

1:02When we compile our software, we take

1:04our source code, which is actually just written

1:06in plain text, just ASCII text-- most source

1:09code can be opened in a software, like, Notepad, right?

1:12It's just plain text file.

1:13And it converts that into a binary executable file.

1:17Let's talk a little bit about what that means.

1:20Imagine you want to feed someone a cake.

1:22Well, you don't have a cake.

1:24What you've got are a bunch of ingredients-- sugar,

1:27eggs flour, milk, whatever is going into the cake.

1:30You can't eat these things.

1:31I can eat these things, right?

1:32I'm not eating spoonfuls of raw flour.

1:34I'm not cracking eggs into my mouth.

1:35I want a cake.

1:36But in order to get a cake, I have

1:38to take my raw ingredients, and I've

1:40got to do some additional steps, right?

1:42I've got to mix them up.

1:43I've got to bake them in the oven.

1:45And then at the end of all that processing, now

1:47I've got a cake, a cake that can actually

1:49be consumed by a person.

1:51Well, I like this analogy.

1:52This is a good analogy for our source code, which

1:55is like our raw ingredients.

1:56That's the code that we are going to write.

1:58Our Python, our C, whatever code we're writing,

2:01is going to be our source code, plain text, inedible

2:04for the computer.

2:05The computer cannot eat that source code.

2:07We have to go through this extra step of compiling before we get

2:10the 1's and 0's, the binary code, which

2:12is also known as an executable.

2:15And you can see this on your computer.

2:17If you have any software installed on your computer,

2:19there is an executable.

2:20For instance, I'm going to bring up my File Explorer in Windows

2:23here.

2:23And let's just look inside of my Microsoft Office folder.

2:26I happen to know where this is.

2:27So I'm going to drill down into the specific location

2:30where it's found.

2:31Look at C Office--

2:32nope, not 15-- 16, right?

2:34Yeah, there it is.

2:35If I scroll down to the Es, I see-- look at this--

2:38EXCEL.EXE.

2:40Application type, the size is 62 megabytes-- a fairly large

2:44binary file.

2:45That file right there, EXCEL.EXE,

2:47is a binary executable.

2:48That is the 0 and 1 instructions that the computer

2:51needs in order to run the Microsoft Excel program.

2:55That's where it's all contained.

2:56That's where the magic is.

2:57And this is true regardless of whether you're

2:59on Windows or Linux or Mac.

3:01There's always a binary executable file

3:03that has to contain all of those instructions.

3:06It's not something you can look at.

3:07If I try to open it up with--

3:09let's see here-- something, like, Notepad,

3:12look at this total gobbledygook garbage.

3:14This is not understandable.

3:15And that's because that EXCEL.EXE is not a text file.

3:19That EXCEL.EXE is a binary executable file.

3:22This is the result of the Microsoft Excel source

3:25code being compiled and being delivered to the end user.

3:29And that's really, at the end of the day, what you

3:31should be thinking about here.

3:32All of these steps prior to the actual cake

3:35is being done by the developers.

3:36It's being done by the person delivering the software.

3:39In the case of Microsoft Excel, that's Microsoft.

3:41They write the source code.

3:42They go through the compilation step.

3:44And they deliver to you, the end user, an executable file.

3:48That is how programming, that is how code, works.

3:51At least that's how it works most of the time.

3:53Now, there are some scenarios where that's

3:56not quite exactly how it works.

3:57And Python is one of those scenarios.

3:59Python-- when you write Python code,

4:01it does not compile all the way to a binary executable.

4:05Python splits up the work a little bit

4:07into a couple of different separate steps.

4:10Now, at the end of the day, we still

4:12have the same basic things.

4:13We still have our source code ingredients written in Python.

4:16And we still have our final cake that is a binary file.

4:19But what we do for Python, as well as other languages,

4:22such as Java or .NET, is we only partially compile it.

4:26We only take it a part of the way

4:28and turn it into something called bytecode.

4:32Now, we won't get too in depth.

4:33But a bytecode file is not binary.

4:36It's not a binary file.

4:37It's not an executable.

4:38A bytecode file is not yet ready to be executed by a computer.

4:42We ship this bytecode file to the end user.

4:45And they have an interpreter installed in their machine that

4:48performs the final execution, the final compilation

4:52of that bytecode into a binary file in real time,

4:55while the file is being executed, while it's being run.

4:57We call this, sometimes, just-in-time execution,

5:00or just-in-time compiling.

5:02This means that our code is not quite finished.

5:06It's not quite baked.

5:07It's parbaked.

5:08If you've ever had a parbaked cake or parbaked cookies

5:11from the bakery, you know that they come partially baked

5:13but not all the way baked.

5:14You need to bring them home, put them in the oven

5:16and finish cooking them.

5:17That's exactly what happens with Python.

5:19So the whole process still has to happen.

5:21We just ship the last final step of that.

5:23We rely on the last final step of the process

5:26to happen at the end user's computer,

5:28the end user's device, when they actually

5:30want to execute the code, when they want to run the program.

5:33So Python code gets converted to bytecode.

5:36This is the process for what we're going through here.

5:39Python code gets converted to bytecode.

5:41The bytecode is delivered to the end user.

5:43And an interpreter, a piece of software

5:45on the end user's machine, finishes running that code.

5:48There's a really important piece that is buried in all of this,

5:51I think, that you need to understand.

5:53And that is the fact that every computer, every device,

5:56every machine that wants to run Python code,

5:58at the end of the day, needs to have

6:00that interpreter installed.

6:02When I compile a C application for saving

6:05Microsoft Windows platform, well, anyone

6:07who has Microsoft Windows installed on their machine,

6:09I know is going to be able to run that application that I

6:11delivered to them.

6:12That's what it needs.

6:13As long as it has Microsoft Windows,

6:14it'll be able to run that.

6:15Not necessarily so with a Python application.

6:18They need not only their operating system,

6:20like, Windows or Mac or whatever it is, they also

6:22need the Python interpreter installed in order

6:25to run my Python code.

6:26That's a really important thing to understand.

6:27It's a really important part of what we're doing here.

6:30And it informs, well, really, it informs the reason

6:32that we do this to begin with.

6:33I mean, after all, what's the point of only doing

6:36this parbaked, partially compiled code

6:38and shipping that to the user?

6:40So let's compare compiling code to an executable

6:43versus bytecode.

6:44When you compile code to an executable,

6:46the executable is absolutely going to run faster.

6:49And it's going to be more efficient in memory usage.

6:51Compiled code, compiled executable,

6:54beats out bytecode on both of those particular notes.

6:56So why do we do it?

6:58Well, because bytecode is platform independent--

7:00it is portable.

7:02It can be delivered to a number of different systems.

7:05The basic idea here is that we have write-once code base

7:12so that we can only manage a single code base

7:15and deliver a single compiled bytecode

7:17executable to all of our different target machines.

7:21Let me expand on this little.

7:22When you compile an executable, say,

7:24in the C++ programming language, if you write an application

7:27in C++, and you compile, let's say, for Microsoft Windows,

7:30let's say you compile it from Microsoft Windows 10.

7:32That's only going to run on Microsoft Windows 10.

7:35Microsoft is good.

7:36It will probably run on Windows 7.

7:38Maybe it will.

7:38Maybe it won't.

7:39It definitely will not run on, say, Macintosh OS.

7:41It will not run on iOS or Android or Linux

7:44or any other platform.

7:45If you want to compile that code for one of those platforms,

7:48you've got to go back and recompile it

7:50with a new target environment, a new target platform.

7:52So you have to deliver different executable files

7:56to different users on different platforms.

7:58And if your code has some instruction for a given

8:00platform that is not supported by another platform--

8:03so I've written some code that works in Windows but not

8:05in macOS--

8:06I can't deliver.

8:07I can't compile that into a macOS executable.

8:10I'm going to have to maintain a separate code base.

8:12Now I have two copies of my source code-- one

8:14for Windows, one for Mac.

8:15Maybe three-- now I need one for Android.

8:17I need one for iOS.

8:18I need all these different copies of my source code.

8:20I have to compile them all independently and separately,

8:22and deliver them independently and separately,

8:25to the appropriate users on the appropriate platforms.

8:28Sometimes that's ideal.

8:29There are certain situations where that's fine,

8:31and you don't mind going through that extra legwork

8:32to get the speed and efficiency gains

8:34that a compiled executable gives you.

8:36But sometimes that's not what you want.

8:37If you don't have a good handle on who your customers are going

8:39to be or what platform they're going to be running on, you can

8:42use something, like, Python or Java or .NET to write your code

8:46one time and one time only-- one single code base,

8:48compiled to one single bytecode.

8:50And you deliver that bytecode to the end user.

8:52You are relying on the interpreter on the end user's

8:55machine, to handle all the complexities

8:57of actually compiling that for the end user's device.

8:59You don't need to worry about it.

9:01If you have some source code that works in Windows and not

9:03in macOS, you deliver it anyways because the compiler is

9:06going to handle not executing that source code.

9:09It will gracefully handle what to do

9:10in that particular scenario.

9:12As a developer, you don't have to maintain separate copies

9:14of your source code.

9:15You don't have to deliver different versions

9:17of your executable depending on your target user's platform.

9:20So you gain a lot of flexibility,

9:21a lot of portability, when you use code

9:24in this way, when you use this method for compiling your code.

9:28So that was all a lot if you're not familiar with compiling

9:30and what we're talking about here.

9:31I talked about a lot of things.

9:33Let me break it down for you one more time before we sign off.

9:36When you write code, you write source code in plain text.

9:38And, in fact, when we write our first Python program,

9:41I'm going to write it in Notepad just to show that off.

9:43Typically you'll use something nicer than Notepad.

9:45But it is just a plain ASCII text file of code,

9:49of instructions, for the computer.

9:50That has to get converted into binary code,

9:52into the 0's and 1's that the computer can execute.

9:55And that is done through a step called compiling.

9:58Most traditional programming languages

9:59get compiled all the way to a binary executable that

10:02is delivered to a target end user's machine for the platform

10:05that they're running, whether it's Windows or Mac or iOS.

10:08Some programming languages, notably, Java, .NET,

10:11and Python, which we are working with here,

10:13only partially compile the code.

10:15They compile it into something called bytecode.

10:17And the end compilation is actually

10:19performed on the end user's machine

10:22while they're executing, while they're

10:23running the application.

10:25They do need an interpreter.

10:26They do need a virtual machine of some sort running

10:29on their computer in order to interpret that bytecode,

10:32In order to run that code.

10:33So you are relying on the end user

10:35already having that support software on their device when

10:38you ship them a piece of, say, code written in the Python

10:41language.

10:42I hope this has been informative for you.

10:43And I'd like to thank you for viewing.

0:05All right, I don't know about you,

0:07but I am ready to start hitting the road here.

0:09Let's get started with Python.

0:11And the first thing that we need to do-- well,

0:13we need to install Python itself.

0:15The Python download can be found at python.org.

0:18And we're going to download a package

0:20and walk through the wizard.

0:21I'll do this on both Windows, macOS, as well as Linux.

0:24So you can see it install on all three.

0:26They all largely work the same, but there

0:28are some unique properties for each platform.

0:30So depending on which platform you're using,

0:32you're going to need to follow slightly different installation

0:34instructions.

0:35Now, there's a few different things

0:36included in the package when we download and install Python.

0:40First of all, of course, our Python interpreter.

0:42Recall that we said in our previous video,

0:45you can't run Python code without a Python interpreter

0:48installed.

0:48Unlike a fully compiled executable,

0:51you need a Python interpreter that can actually

0:53read and understand the bytecode that gets delivered

0:55and then in turn execute that on the target machine.

0:58The target machine in this case is going of the our computer.

1:00So the Python interpreter is installed.

1:02There's also something known as an integrated development

1:05environment for Python called IDLE.

1:06This is a very simple IDE.

1:08I'm going to show it briefly in another video,

1:10but I don't think we're really going to use that much.

1:12Certainly, if you want to use IDLE, you're welcome to,

1:14but you don't need to worry too much about it.

1:16Just know that that's an environment where

1:18you can type Python code in, and it

1:20has some shortcuts and useful features

1:21and utilities that will help you write Python code.

1:25The Python installer also has something called pip,

1:27the package installer.

1:28This is how we install additional separate utilities

1:32that are not actually included in the Python 3 downloads.

1:34So there is a whole universe of libraries and updates

1:37and options and features and things that Python themselves

1:40have developed, as well as the wider community.

1:42There's thousands and thousands and thousands of packages

1:45out there that you can download that do things for you.

1:47Pip is going to be the way that you

1:49get a hold of those packages and install them on your system

1:51so that you can use them inside of your Python code.

1:54We'll get the standard libraries installed as well.

1:57So aside from the pip package installer,

1:59there is a host of libraries that

2:01get shipped standard with Python and are installed

2:04with the Python software.

2:05Those will come.

2:06And then lastly, it is going to set up our file and path

2:09associations.

2:10That's a feature I'm going to talk about

2:12in a different video, but that's a really important thing

2:15to understand to set up in your Python installation.

2:19To begin with, I am going to open up python.org and come

2:22over here to Downloads.

2:22And I'm going to download Python.

2:24Well, the current version is 3.9.2.

2:27Note that it cannot be used on Windows 7 or earlier.

2:29So if you are not on Windows, this

2:31should pop up with the appropriate platform for you,

2:34either macOS or Windows.

2:36I'll click Download so I can download this file.

2:39And once it's complete, I will click

2:41it to execute it and go through the installation process.

2:44Now, you can just click this Install Now if you want.

2:46That will install with all the default features.

2:48There's absolutely nothing wrong with that.

2:50The only thing I don't like here is

2:51where it chooses to install the software.

2:53It's buried down here instead of my user profile on Windows.

2:56I'm not a huge fan of that.

2:57I'm going to say customize installation.

2:59I'm going to leave everything the way

3:01it was except for this part right here.

3:03I'm going to change this to C colon backslash Python39.

3:08This is going to install it inside

3:10of the Python39 folder on my root C drive on my computer.

3:13And as I will show you in a minute, there's a lot.

3:17I'll also check Install for all users.

3:18I think that'll be good.

3:20Click Install.

3:21And this will install Python for me.

3:23Very simple and straightforward, not a difficult thing

3:26to do on any of these platforms.

3:28It's pretty streamlined.

3:29The process, it's fairly easy to do.

3:34That took a few minutes to complete, but once it's done,

3:36you get the "Setup was successful."

3:38And Python is now installed on your machine.

3:40I will show you how to check that out in just a moment.

3:43Let's walk through this same process, however, on Macintosh

3:46OS.

3:47Here is my Mac OS desktop, and same thing, I'm at python.org.

3:51If I come over here to Downloads,

3:52notice now it's Download for Mac OS X. Click the link

3:56and let that download.

3:57And once it's done, I will select it in order

4:00to kick off my download.

4:02Now for Mac, I am just going to click through all

4:05of the wizard options.

4:06I don't think there's anything that I'm

4:07really interested in changing, including

4:08the install location-- not something

4:10I need to update on my Macintosh system.

4:13I'm just going to let it install Python 3.9.

4:16Once again, this should just take a second or two.

4:20And there it is.

4:21It's complete.

4:21It's showing me the file.

4:22Notice there's the IDLE application,

4:24that IDE that we talked about, Python documentation,

4:27a launcher, a number of different things here.

4:30We're almost ready to get into it.

4:31Let's take one more quick look at how

4:33I do this in the Ubuntu software, Linux.

4:36Now, unfortunately, Linux is too rich

4:38and varied of an environment for us to really make

4:41a universal installer video.

4:43I'm going to show off how you do it in Ubuntu using the APT

4:46software.

4:46This is a pretty common way to do things.

4:48So it may well work on the version

4:49of Linux, the distribution that you're using.

4:51If it doesn't, you're going to have

4:53to hit your favorite search engine

4:55and look up how to install Python.

4:56It ought to be pretty straightforward, pretty simple.

4:59So from my terminal, I am going to call

5:02apt-add-repository to add a specific repository to my APT.

5:08It's going to be something known as the deadsnakes, which

5:11is a funny name, but that is where the Python application

5:15is installed here.

5:17And once that catalog is installed inside of my package

5:20library, I can now call sudo apt install python3.9.

5:25This will install Python version 3.9 for me.

5:28Get this installed here.

5:30Once this is complete, I can verify at the terminal window

5:34that Python is installed.

5:35Let me show you how to do this quickly in my terminal here.

5:37Then I'll launch up my Windows terminal

5:38and show you a little bit about what we've done.

5:41So there.

5:41It appears to be complete.

5:43I'm going to call python3.9 --version.

5:48And this is going to show me that, yep, it

5:49responded with Python 3.9.2.

5:52I now have that installed.

5:54Let me open this up in Microsoft Windows

5:57and do something similar.

5:59So here I'm at a Command Prompt, a terminal

6:01window in Microsoft Windows.

6:02By the way, you can do the same kind of thing in macOS

6:05as well, if you're familiar with how

6:07to launch the terminal here.

6:08I'm just going to call python --version and see what I get.

6:11I get 3.7.4.

6:13And the reason for that is because of the fact

6:16that I have multiple versions of Python installed.

6:18And my path version currently points to version 3.4.

6:22If I go cd backslash python39, is where I installed it,

6:26take a look at this directory-- yeah, there's python.exe.

6:29So now when I run Python, it's going

6:31to run this local version.

6:33I'll talk about paths in the different local versions

6:35in my next video.

6:36But python --version in here is now Python 3.9.2.

6:41So if I want to execute Python 3.9,

6:43presently I've got to make sure I'm right here

6:45inside of this folder.

6:46I've got a lot of different versions of Python installed,

6:48like I said.

6:49If I go back to 27, I think I have 27 installed here as well.

6:53So I could call python --version 2.7.17.

6:56So like I said, I've got a number of different versions

6:59of Python installed.

7:00You may only have the one.

7:01But if you have multiple versions,

7:03you need to make sure that you either

7:05change into the proper directory or that you set up

7:07your path variable the way I'm going

7:09to show off in my next video.

7:11But here, all I want to do is run Python without --version.

7:14This launches me into something known

7:16as the interactive terminal.

7:18You see those three little arrow brackets there?

7:20In the interactive terminal, I can just

7:22start typing Python commands, and the Python interpreter

7:24will execute them as I type them,

7:27which is actually pretty cool.

7:28It's a neat way to test out quick little bits of code,

7:31which is exactly what we are going to do right here.

7:34If you've got Python installed, you have the correct version,

7:36you ran Python, you have these three little pips right here,

7:39you can do what I'm going to do, which is to say print("Hello

7:41World!") and hit Enter.

7:50And you can see, it just echoed right back to me, Hello World!

7:53OK, yeah, I get it.

7:55That's not especially exciting, but it

7:57is a traditional first program and that

8:00is absolutely a complete and functional Python program.

8:03Print("Hello World!"), that is a Python program.

8:08If you've done this, if you've gotten this far,

8:10you have written your first Python program,

8:12and we have written our first Python program together.

8:15In my next video, I'm going to talk a little bit more

8:17about configuring our environment

8:18and setting up the path, as well as the code

8:21editors that we want to use.

8:22I hope this has been informative for you,

8:24and I'd like to thank you for viewing.

0:05I'd like to take a few moments here and dive

0:07into the weeds a little bit on some system

0:09administration, some configuration

0:11for our installation of Python.

0:13And I touched on it briefly in my previous video

0:15where we installed Python, but now

0:17I want to take a moment to really dig into it,

0:19and what it means, and what we saw.

0:21So here's what we're starting with.

0:23Python, when we install it, gets installed

0:25to a specific directory on our computer.

0:28It had a default directory.

0:29I actually overwrote it, if you recall and watched that video

0:32on me installing it.

0:33So I installed Python 3.9 to a specific directory.

0:36But we can only execute the Python interpreter,

0:38the python.exe file, to interpret and run

0:41our Python code if our user context is in that directory.

0:45And I'll show you what I mean by user context in a moment.

0:47We saw this briefly.

0:49When I launched Python --version after installing it

0:52and I was just in my root C folder,

0:55it returned version 3.7, not version 3.9.

0:58And that's because I had both 3.7 and 3.9 installed

1:00in my system.

1:01But specifically, there was something

1:02known as an environment variable that was pointed

1:05towards the Python 3.7 path.

1:08Now, we could have changed this.

1:10In our installation of Python, you

1:12may have noticed that I breezed past this screen.

1:15But during installation, we had this little option here,

1:18Add Python 3.9 to PATH.

1:21I do not check that.

1:22I would probably actually recommend

1:24that you do check that, but I specifically

1:26left it unchecked to put myself in this scenario

1:29so that I could show off exactly what has happened here.

1:32So what that means is that we need

1:33to open up and add Python 3.9 to our environment variables

1:38itself.

1:38I'm going to show you how to do this in Windows.

1:40I'll briefly take a look at it inside of Mac

1:42so that you can understand how it works in bash.

1:44Mac and Linux work largely the same.

1:46Windows is quite a bit different,

1:48although the functionality is the same across all

1:50of these different platforms.

1:51The first thing you're going to do,

1:53if you are on the Microsoft Windows platform,

1:55is open up your Start menu and type in environment variables

1:58to get this particular link up here,

2:00Edit the system environment variables.

2:03When you click that link, it will

2:04launch this particular window right here.

2:06And notice this button right in the bottom,

2:08Environment Variables.

2:10Environment variables are basically

2:12values that are available to the entire environment,

2:14the entire system.

2:15They come in two forms.

2:16You can see them here.

2:18At the top are the user variables, and at the bottom

2:20are the system variables.

2:22Basically, system variables always apply.

2:24User variables only apply to the specific user

2:27that is logged on.

2:28So user variables can change from user to user.

2:31I'm logged on as CBTBen right now.

2:32If a different user logged in, these values

2:35might be different for that user,

2:37whereas these values would all be the same because they

2:39apply to the entire system.

2:41Both of these have a specific variable

2:42that I'm interested in called PATH.

2:45And again, the user variables, if they duplicate up,

2:47will overwrite the PATH of the system variables,

2:50so keep that in mind.

2:52But let's take a look at the PATH variable itself.

2:54The PATH variable contains a number of different directories

2:57on my system and effectively makes the executables

3:00in those available from anywhere.

3:02So notice, Python37 is included right here--

3:06C colon backslash Python37.

3:08Why is that important?

3:09Well, if I come here into my C colon

3:12and I type Python --version, what do I see?

3:16Python 3.7.

3:17I'm not in the Python 3.7 folder right now,

3:19I'm just in the root folder.

3:21But Windows recognized that it went through the script

3:24and it was able to find python.exe

3:26located in the 37 folder.

3:28If I were to remove this from my environment variables,

3:32so that now Python 3.7 is no longer located in there,

3:36check out what happens now if I actually close this and start

3:39up a new one.

3:41So this is a new command prompt.

3:42When I run Python --version now, I get, Python was not found.

3:46It can't see it.

3:47My user context is currently located in the root C colon

3:51folder, which means there is no python.exe file.

3:54I can only run Python if I change my directory

3:58into that folder.

3:59So if I cd backslash into Python39, for instance,

4:03now I can write python --version and get Python 3.9.2.

4:08But if I'm not inside that folder-- for instance,

4:10if I'm in a folder mysourcecode, how about,

4:14there's no Python installation here.

4:16In fact, there's nothing at all in this folder.

4:18I can't run Python from here.

4:19I get-- well, in this case, it tries

4:21to launch the Microsoft Store and install it.

4:22But it does not run the locally installed copy

4:25of this software.

4:26Now, there's a couple of solutions here.

4:28One, I could always just explicitly reference

4:30them using the full path name, so I

4:32can call python39 backslash python, like this,

4:36and this will execute the Python software for me

4:38by explicitly referring to the version that I want to run.

4:41If I change it-- instead of 39, if I go 36--

4:44do I 36 installed?

4:45I don't.

4:46Oh, I have 3.8, I bet. python--

4:48yeah, there's 3.8.2 installed in Python38.

4:50So I can always reference the specific version,

4:52the specific Python executable that I

4:54want to run by putting the full path in.

4:56But you know, that's a lot of typing.

4:58There's a lot of extra typing.

4:59And if you've only got one version of Python installed

5:01and you only ever need to run that one version of Python,

5:04why not just stick it inside of your PATH variable?

5:06Come here to Environment Variables.

5:08I'm going to come down to PATH right here and say Edit.

5:11And let's add a new entry here, C colon backslash Python39

5:16backslash.

5:17I'll say OK, OK.

5:19I do need to restart my Command Prompt.

5:22And I will change directory into mysourcecode again.

5:26There we are.

5:27Now I can run python --version and it comes up with 3.9.2.

5:31Because I added it to the environment variable,

5:33Windows now searches that PATH, finds a Python executable,

5:37and runs it when I try to execute it here.

5:40We can also do something similar inside of other operating

5:43systems, such as Macintosh.

5:44So for instance, from my Macintosh computer here,

5:48if I launch my terminal window--

5:49I have iTerm installed.

5:51I also have a user context.

5:53This launches me instead of my home directory, benjaminfinkel.

5:56And if I want to run Python, I call python --version-- yeah,

6:012.7.7.

6:02That is what's currently pointed towards in my PATH.

6:05How do I know?

6:05I can call echo $PATH, and that shows

6:10me all of the different folders, all the different locations

6:12that are included inside of my PATH variable.

6:15Now, I'm not going to spend a whole lot of time

6:17getting involved in the Linux and macOS PATH

6:21variables that are located in bash.

6:23You can look up Shawn Powers's excellent Linux administration

6:27course.

6:27And there's a video there about environment variables that

6:30covers all of this in depth.

6:32Functionally, it's effectively the same as what I just

6:34showed you inside of Windows.

6:36You need to have the actual location of the Python

6:38executable file inside of your PATH folder

6:41so that it can be run, it can be executed from any location,

6:44regardless of where you are inside of the terminal window.

6:47All this allows us to run Python from our Command Prompt,

6:50from our terminal windows, regardless

6:52of which folder in, regardless of which directory

6:54we're currently located in, so that we can put our source

6:57code in a different directory than the Python interpreter

6:59and so that we can have multiple versions of Python installed

7:02on our system and explicitly know

7:04when we want to run one version versus another.

7:07I hope this has been informative for you,

7:08and I'd like to thank you for viewing.

0:05BEN FINKEL: If you have been following along

0:07with these videos, then you should

0:08have downloaded and installed Python on your system,

0:11opened up the Python interactive editor,

0:13and typed in a line of code and see it run.

0:16That's a cool thing to do.

0:17If you did that, give yourself a little applause.

0:19If that's the first code you've ever written,

0:21hey, that's a big step, and I don't mean to diminish it.

0:24But it is only the first step on a very long journey

0:27that is going to involve a lot of different things.

0:29And one of the first things that we wanna change

0:32is we don't want to spend a lot of time inside

0:34of that interactive editor.

0:35In fact, I'm not going to do that at all.

0:37I think you want to get out of the habit right away

0:39of using the interactive editor with Python.

0:42It's great to just hammer out a line of code or two,

0:44and see it run, and see how it works.

0:46But the second you get above more than like two

0:48or three lines of code, it's no longer really

0:50a useful interface to be working in.

0:52Instead, what you prefer to be doing

0:54is writing source code instead of a source code file,

0:57and then saving that file to your file system.

0:59Now, if you'll recall, I've mentioned a number of times

1:01during the series that source code is saved as plain ASCII

1:05text and saved as a plain ASCII text file on your file system.

1:09And this has a couple of different implications .

1:12The one that I've been talking about

1:13is the fact that source code files need to be compiled,

1:16either to bytecode or all the way to an executable,

1:18before they can actually be executed

1:20on an end user's system.

1:22But it also means that they're kind of universally portable.

1:25ASCII text, if you're unfamiliar,

1:27is just a plain basic text format that computers use.

1:29If you use Notepad in Windows, or I

1:31think it's called TextPad inside of macOS--

1:34these are the types of files that those file editors edit.

1:38It's just plain text.

1:39And if you create a source code file, it's saved as ASCII text.

1:43While not technically universally portable,

1:45it's, in practice, universally portable,

1:47because almost every system out there--

1:49every device, whether it's a tablet, a phone, a laptop,

1:51a desktop, whatever it is, cars and washing machines,

1:54anything that has a computer in it

1:56can probably read a text file.

1:58And that is true of your source code, as well.

2:00And what that means is that we could write our source

2:02code, if we wanted to, in something as simple as Notepad.

2:06You know Notepad, right?

2:07It's the basic editor that is built inside of Windows.

2:10It looks something like this.

2:12I got it on screen here.

2:13This is a Notepad editor.

2:14And yeah, actually, this is a functional Python program

2:17inside of Notepad.

2:18Don't worry about what this.

2:19Does we'll talk about it in a little bit.

2:21But the point is you could write your code inside of Notepad.

2:24I've done that exactly right here.

2:25I have this text written out, saved as samplecode1.py.

2:30I'm going to open up my command line,

2:31and inside of mysourcecode, I believe

2:33that's where I saved that file.

2:34Yep, samplecode1.py.

2:35I'm going to say python samplecode1.py.

2:39This is going to execute my Python interpreter,

2:42passing in that file.

2:43So instead of working in the interactive interface

2:46for my Python interpreter, I have code written to

2:50and saved to a file, and it's going

2:51to execute all of the code inside of that file for me.

2:54So we will click Enter here.

2:56"What is your name?"

2:57Well, my name is Ben.

2:58"How old am I?"

2:59Well, at the time of this writing, I'm 42.

3:01It says, "Hello Ben.

3:02You're old enough to vote in the US!"

3:03Hey, I am old enough to vote in the US.

3:05That's true.

3:06Let's test out this program.

3:07I'm going to run it one more time.

3:08"What is your name?"

3:09My name will be Dolly.

3:10"And how old are you?"

3:11What if Dolly is 17?

3:13"Hello Dolly.

3:14Wait a few more years before you can vote in the US."

3:16That's absolutely true.

3:17You can only vote in the US once you're 18 years old.

3:20So this code, this program was written here in Notepad.

3:22And yeah, OK, technically, yes, you can write your code,

3:26you can write your software in Notepad.

3:28I don't recommend that, either.

3:29I don't recommend it any more than I recommend

3:31using the interactive interface that comes with Python itself,

3:34because while yes, you can edit the actual text of your code,

3:38Notepad offers exactly zero additional features, zero

3:41support to help you write better code,

3:43or to help you understand the code that you're writing,

3:45or to help you navigate, and organize,

3:46and architect your code.

3:48There's a lot of benefits to using

3:50other tools, additional tools, for writing our code.

3:55So some of those tools are known as IDEs--

3:58Integrated Development Environments.

4:00You may have heard of these.

4:01They're pretty popular.

4:02There's a lot of them out there.

4:04This is going to be things like Visual Studio, Eclipse,

4:08NetBeans.

4:08There's a lot of different IDEs out there.

4:10And IDEs are these really big, robust, complex but powerful,

4:15feature-rich tools.

4:16They allow you to do a lot.

4:18They are really designed and built from the ground up

4:20to write and architect large-scale enterprise

4:23applications and software.

4:25They will have built in harnesses for testing,

4:27for source code control, for bringing in libraries,

4:31for linking in different types of code

4:33and different types of software, even things

4:35like navigating databases.

4:36There's a lot of features inside of these IDEs.

4:38And that's great, right?

4:39If you need that power, if you need that flexibility,

4:42by all means, go for that.

4:43But the challenge there, of course,

4:44is that they're very complex.

4:46The learning curve on these is very, very steep.

4:48It can take a long time to learn an IDE.

4:50And on top of that, typically, they

4:53have a fairly high cost associated with them.

4:55Not always-- there are some really good,

4:57powerful, free IDEs out there.

4:58But most of the really good ones, most of the ones

5:00that people use, are going to cost a little bit of money.

5:04So by all means, if you want to use an IDE,

5:07if you are already familiar with an IDE

5:09or your organization already relies on one

5:10and has the licenses for it, use that IDE to write Python.

5:13You may need to look up how to install

5:15some extensions to support Python development,

5:17or maybe it supports Python development right out

5:19of the box, but it's likely going to be a good choice.

5:22It's just going to be a bit more of a complex point

5:24to enter into this whole process.

5:27On the flip side, the total opposite of the IDE

5:30is the text editor.

5:31Now, I'm not just talking about Notepad.

5:33I showed you Notepad a moment ago.

5:35Notepad is nothing.

5:36Notepad allows you to do nothing more than just edit text.

5:39I'm talking about these text editors that are kind of robust

5:43and kind of a big step up from Notepad.

5:45They are typically very lightweight,

5:47so they're small to download.

5:48They don't take up much memory.

5:50They run quickly.

5:50They run fast.

5:51They're usually a lot easier to use than an IDE.

5:54Because they have so many fewer features,

5:56their interfaces are a lot less complex.

5:58They cover the basics, really the nitty-gritty details

6:00of what you need to write code, but they don't have

6:03a whole lot of extra stuff.

6:04One of the cool things, though, is the modern text editors

6:07that we use a lot are often extensible.

6:09And that is true of both of the ones that I've got up here,

6:11Sublime Text and Notepad++.

6:14Just like the name implies, Notepad++ is meant to be sort

6:18of Notepad but on steroids.

6:19It's a better version of Windows Notepad.

6:21It's available on every major platform as an editor,

6:24and it looks a little something like this.

6:26Here is that same Python source code open in Notepad++.

6:30And notice two big differences here?

6:31Well, one, we've got a whole toolbar full of options

6:34up here that do different things, that

6:35might do some interesting different stuff.

6:37And two, notice that some of the text

6:39down here has been colored in.

6:41That's important.

6:42We call that syntax highlighting.

6:43You're going to see that in all of the additional code editing

6:45options that I show you here.

6:47It's one of the most basic features that a code

6:48editor is going to offer and one of the most important.

6:51Syntax highlighting helps you understand your code better.

6:53So if you're using a code editor,

6:55make sure it has syntax highlighting specifically

6:57for the Python language.

6:59Sublime Text is another one similar to Notepad++.

7:03Notepad++ is free.

7:04Sublime Text does have a small fee associated with it,

7:07but I would highly recommend it.

7:08This is one of my favorite text editors.

7:10I use it a lot.

7:11Sublime Text looks like this.

7:12Again, you can see the syntax highlighting

7:14that we saw in the other one-- even more so.

7:17There's even more syntax highlighting than there was

7:19inside of Notepad++.

7:21Sublime Code and Notepad++ both offer extensibility.

7:24They both have plugins that can be installed.

7:26So they are really, really good choices.

7:28I would recommend those both as choices

7:30to get started with editing your code.

7:33But that's not the one that I want

7:34to use in this video series.

7:35In this video series, I want to use something that's,

7:38well, kind of in between the two,

7:40in between text editors and IDEs.

7:42I think they're often referred to as IDEs,

7:44but I'm gonna to call them code editors.

7:46And there's two major ones that I want to discuss.

7:49There's a lot of different options

7:50out there in this space, as well.

7:52If you haven't figured it out already,

7:53there's a lot of code editors in general

7:55that you can use in a lot of different ways.

7:56It all comes down to personal preference.

7:58But the two that I'm going to talk about

8:00are Atom and VS Code.

8:01And really, I'm just going to focus on VS Code.

8:04Atom is a free, lightweight text editor, code editor,

8:07similar to Sublime but a little more robust.

8:10This is what an Atom code looks like.

8:12Oh, and let's see here.

8:13You can find it online at atom.io.

8:16This is the download page for it.

8:17It's going to run on all the major platforms,

8:19just like all the rest of these options that I've shown off.

8:22And Atom allows you to browse your code as a sort of project.

8:25So I have my folder over here as a project.

8:28Here's my code with syntax highlighting built-in.

8:30This is just with the default, nothing additional installed

8:33or setup.

8:34It will allow me to do some interesting different things,

8:36like connect up to GitHub for source code control.

8:39It's going to have some built-in harnesses

8:41for testing, and for running my code, and running my packages.

8:44But by no means is it a full-fledged IDE,

8:47like something like NetBeans.

8:48It's much simpler than that.

8:50The one that I'm going to use, my favorite code editor,

8:53is one called VS Code.

8:54And VS Code looks like this.

8:56I'm going to spend a lot of time here inside of VS

8:58Code throughout the rest of this video series on Python,

9:01so get used to seeing this interface.

9:03Now, VS Code can be downloaded for free.

9:05It's also a free piece of software, found here

9:08at code.visualstudio.com.

9:10And download it for your platform.

9:11It runs on Mac, Windows, and Linux.

9:13It looks and works the same on all of them.

9:16The installation is largely wizard-based,

9:18so I'm not going to walk through that.

9:19You need to download the executable, run the executable,

9:22and get VS Code installed.

9:24Your VS code will not look exactly like mine

9:26when you install it.

9:27I've gone through some customizations on it.

9:29You can watch my videos on installing and setting up

9:32VS Code for your development environment

9:33here at CBT Nuggets, that walk you through, soup-to-nuts,

9:36how I like to configure and set up VS Code to work for me so

9:40that it will look like this.

9:41But don't worry if it doesn't look like this.

9:42The basic installation of VS Code works great.

9:44You don't need to worry if that's what yours looks like

9:46and you want to keep it that way.

9:47That's perfectly fine, too.

9:48This is all just fine-tuning the aesthetics of the software

9:51itself.

9:51One thing that I do want to do, I do want to show you,

9:54is over here, this little option right

9:56here is called Extensions.

9:57And this is where I install any extensions that I

10:00want to install on my Code.

10:02Notice right down here in the recommended, it says Python.

10:04I've got a Python file open.

10:05It's like, hey, you may want to install Python.

10:07If you don't have that, you can search up here for Python.

10:11Give it a click.

10:12And notice that it has 33 million downloads, five stars.

10:15This is a popular common Python extension for VS Code.

10:20You're going to want this installed in your VS Code

10:22software.

10:22You just click that purple Install button and it's done.

10:25It says-- what does it say?

10:27Some features may not be available

10:28until interactive window session is restarted.

10:31That's fine.

10:32So I've installed the Python extension now.

10:33That is now available to me inside of my code.

10:36And I can run and execute my Python scripts

10:40from right here inside of VS Code.

10:44One thing that I would like to note down here

10:46in the lower left, it says Python 3.9.2 64-bit.

10:50Let me shrink this up so it's on screen for you here.

10:53So if you hover over that, it says

10:54c colon backslash Python39 backslash python.exe.

10:58If you recall, that is where I installed

10:59Python 3.9 in my earlier video.

11:02So VS Code was able to automatically find

11:05that installation for me.

11:06If you wanted to run a different version,

11:07you could just click this, and I can

11:09go choose different versions of Python

11:11that are found in different locations on my computer.

11:13For the specific interpretor executable that I want to use,

11:16I am, of course, just going to leave it at Python 3.9.2.

11:19That is the reason I installed that,

11:21because I want to use that.

11:22So this code up here, I can run using the key F5, or up here

11:26on the menu, F5, Start Debugging.

11:28I want to run the Python file.

11:30It's going to launch this inside of a new terminal

11:32window that is built right in here into VS Code.

11:35So if you recall, earlier, I ran this in a terminal window

11:38in Windows.

11:38And it said, "What is your name?"

11:40That same thing is now happening down here inside

11:42of the terminal in VS Code.

11:43My name is Ben.

11:44How old am I?

11:4542.

11:45"Hello Ben.

11:46You're old enough to vote in the US."

11:48All right.

11:48So there you have it.

11:49That is my personal preference for code editors

11:52for development in Python.

11:54VS Code, I think, is a great choice.

11:56But if you don't want to use VS Code, you can use Atom,

11:58Sublime, Notepad++-- really, any of the options that I mentioned

12:01in here are fine, with the exception of Notepad.

12:04Don't use plain Notepad.

12:05That's just a bad idea.

12:06By using these code editors, you're

12:08going to get syntax highlighting.

12:09You're going to get all sorts of benefits and features that

12:12will help you write good, clean, effective code,

12:14and also help you read your code, which

12:16is a big part of development, as well

12:18as looking at, and reading, and understanding code.

12:20So that is what I recommend.

12:22By all means, you make your choice,

12:23the thing that you feel most comfortable with,

12:25the editor that you feel most comfortable with.

12:26If you are brand new to programming,

12:28I would recommend downloading and starting with VS Code

12:30and watching my series on getting VS Code configured

12:33and setup on your system.

12:34I hope this has been informative for you,

12:36and I'd like to thank you for viewing.

0:05OK.

0:06Wow, we have covered a lot.

0:07We have looked at what a programming language is,

0:10and why we need to use a programming language.

0:12We have downloaded and installed Python on our system.

0:15We've configured our environment variables.

0:17We've talked about code editors.

0:19You know what I'm ready to do?

0:20I'm ready to write our first program.

0:22I know.

0:23I know.

0:23I said earlier that we wrote our first program

0:25when we did a little print statement instead

0:27of the interactive Python terminal.

0:28Actually, I don't think that counts.

0:30I think I want to write a piece of code inside of a Python file

0:34and execute that script, execute that code with Python.

0:37So let us first make sure that we are completely

0:40prepared for what we need.

0:41And that means that you should have gone through the earlier

0:43videos and accomplished or succeeded at all these tasks.

0:46You should have installed Python.

0:48You should have chosen your favorite code editor,

0:50and downloaded and installed that code editor.

0:53And you should add any Python extensions to that code editor

0:56that you might need.

0:57If you don't have all of this done,

0:58if you aren't ready with something

1:00like VS Code or Sublime Text to start writing some code,

1:03go back and watch those videos and make

1:04sure you've understand all that, you've

1:06gone through those steps.

1:07That's the only way you'll be able to follow along

1:09with what we are doing here.

1:10And that is exactly what we need to do now,

1:12so that we have this up and running.

1:14Let's write some code.

1:16I'm here inside of Visual Studio Code.

1:19And I have mysourcecode folder open.

1:21I did that with File, Open Folder.

1:23I chose mysourcecode in C colon.

1:27There it is.

1:27And you can see there's already that file

1:29that I was working with in an earlier video, samplecode1.py.

1:33I'm not going to use that.

1:34I'm going to do a new file.

1:36I will call this firstprogram.py.

1:40Using the .py is very, very helpful for VS Code.

1:43That's an indicator to it that it is a Python program.

1:46Notice that when I do that, the icon

1:48changes to that blue and yellow kind of squirrely thing,

1:50the Python icon.

1:52So by calling it .py, that tells Visual Studio Code,

1:55this is a Python file.

1:57Let's write some code.

1:58This is going to be a very simple program,

2:00but is going to be more interesting than just printing

2:02out, hello world.

2:03If you want to follow along, you need

2:05to follow along very explicitly with what I type in here.

2:08So I'm going to say, username = input,

2:12and then open parentheses.

2:13And notice, it put the closed parentheses in there for me.

2:16That's called autocompletion, a nice feature of an IDE

2:19or a code editor.

2:21A double quote.

2:21And then inside the double quote, I'm going to say,

2:23What is your name?

2:27And that's it.

2:28I'm going to go to the end of line and Enter down.

2:31Like I've said in the past, coding is very specific.

2:34It's very precise.

2:35Those parentheses, those quotes--

2:37those are important.

2:38You can't mess those up-- the equals sign.

2:39It's important, even though you don't understand

2:41what's going on here just yet--

2:43I'm not worried about explaining to you how this code works.

2:45I just want you to type it in and follow along.

2:47It is important that you type it in exactly as you see it.

2:49And this file will be available in the Supplemental Files

2:52to download at cbtnuggets.com, so you can certainly

2:55compare what you type compared to what I type, in case you get

2:58lost or confused, or something's not working right.

3:00Having done that, we now have-- well,

3:02you don't need to this just yet, but we have a variable named

3:05username that will get populated with what the user types in.

3:07I can now print out to the terminal

3:10another open parentheses, another double quote,

3:13Hello there space, close quote.

3:16But after the close quote, before the close paren,

3:18I'm going to do space plus username

3:22then my close parentheses, just like that.

3:25So now, instead of one line, it's two lines long.

3:27I realize it's not a big change.

3:28It's not a big update.

3:29But you know what?

3:30It's a cooler first program than just hello world.

3:32It actually has some interaction with the user.

3:35Last thing, you need to make sure

3:36that you are set up on your Python executable

3:39if you want to execute it inside of the Visual Studio Code

3:42editor, like I do.

3:43Down here, it should say Python 3.9.2 64-bit.

3:47You should hover over it and see the installation

3:49for your Python executable.

3:50If it doesn't, it's very easy to fix.

3:52Just give it a click.

3:54Type Enter interpreter path.

3:55You can either type the path in directly here, or click Find,

3:58and this will allow you to browse

3:59your system for the exact interpreter that you want.

4:02So if I wanted to run this with Python 3.8,

4:03I could change it to Python 3.8 right here.

4:06I'm going to leave it at Python 3.9.

4:07Open up that.

4:08Select python.exe.

4:10I have now selected the Python interpreter.

4:13The keyboard command F5, or the menu Run, Start Debugging,

4:17will execute this code.

4:19It's asking me what I want to run.

4:20I can choose the top option here,

4:22Debug the currently active Python file.

4:23That is absolutely true.

4:24That's what I'm using.

4:25It will launch a terminal window down here

4:27on the bottom half of my screen for me, launch the program,

4:30and it asks right away, "What is your name?"

4:32My name is Ben.

4:33And when I hit Enter, it says, "Hello there Ben."

4:36If you want to execute this code outside the confines of VS

4:38Code, well, that's easy enough to do.

4:40For instance, if I bring up my terminal window here--

4:42this is just my Windows Command Prompt--

4:43here instead of mysourcecode, I've

4:45saved that code to firstprogram.py.

4:47So I can absolutely say python--

4:50if I spell it right--

4:51firstprogram.py.

4:53This is going to run my code.

4:54There it is.

4:54"What is your name?"

4:55My name is Joe.

4:55"Hello there q

4:57So we've written and executed our first program,

5:00our first Python script.

5:01It's saved as a plain text file with a .py extension,

5:04but Python can interpret and execute that on our system

5:07because we have Python installed and because we know how to run

5:09our code.

5:10Congratulations.

5:11We've done it.

5:12It's a small first step, but it is

5:14a first step on the journey of Python coding.

5:16We have written an interactive piece of software,

5:19an interactive piece of code, an application that runs

5:22and interacts with the user.

5:23I hope this has been informative for you,

5:25and I'd like to thank you for viewing.