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Welcome to your first video on Python.

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So in this python series we're going to cover a lot of different topics and we're just going to build

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upon them slowly so that everything builds kind of upon the last less it.

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So in this first lesson we're gonna be talking about strings and we're going to be working primarily

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in Python 3.

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So quick thing to note is that my Cally interface might look a little bit different.

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I'm on my personal pen test machine here.

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The only reason I'm doing that is because when we get into the text editor my text editor on the newer

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version of Kelly would not let me edit my preferences very easily so I went ahead and just went back

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to my machine that has an older text editor on it so you can follow along completely step by step in

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your your Cally and you should be fine.

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I just wanted to make sure that the font size is good enough for the recording.

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So from here let's go ahead and make a new directory and I'm just gonna call this directory python and

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then we're going to change directory into Python and the first thing we're gonna do is we're going to

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get it and I'm just going to call this first dot PI.

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This will be our first python script and we're gonna build on it.

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So the first thing we need to do is declare what it's called a shebang.

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So that is a hash bang like this and we're just going to declare bean Python 3 here at the top.

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Now what is this do.

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This allows us to know or the Linux to know when we run this say we were to run this like Python 3 and

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then we just say first stop pi if we run it like this then Python interprets the hash here which you're

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going to learn a little bit as a comment.

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So all this is commented out we don't worry about it but let's say we wanted to run this a different

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way.

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We want to say dot forward slash first stop pi then it would actually be interpreted here at the top.

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So let's go in here and read this.

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It would say hey this I'm going to go ahead and look for bean Python 3.

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It's going to find Python 3 in bean because that's where it's stored and then it's going to use that

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to execute Python or this python script here.

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So we have two ways of running it.

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We can either run it Python 3 first at Pi or we can run it as you've seen it with some of our other

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scripts with the dot slash like this.

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So I always like to declare at the top it's not necessary if you're just going to type in Python 3 but

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I always like to do it.

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So I'm going to give you some headers here so I'm just going to put a comment in and it's going to say

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print strain.

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And so the first thing we're going to do is print a string.

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Now in the very stereotypical lesson the very first string that most people print is the hello world.

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So we're gonna go ahead and just do that.

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So let's go ahead and print Hello World and we're going to do that by just typing in print and then

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in parentheses with quotation and we're gonna say hello world.

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Something like this.

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OK and that's it.

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So what we can do here is we can just save this and we can go ahead and give this a go.

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So what we'll do is we'll say Python 3 and then we can say first in an auto tab out to first stop pi

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and you can see now that it wrote out hello world.

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So if we go up twice and go back to our g at it we can see here that it ignored printing out anything

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here with the comment it didn't interpret this because this is a comment with the hash and we just told

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that one instruction which was to print Hello World and it did just that.

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So the nice thing about strings is we could use double quotes or we could use single quotes so we could

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say sorry hello world like this and we can also use multi line strings so I'm going to tab or hit enter

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twice here and we could say something along the lines of print and what if we have a long quote We could

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say something like this string runs and then we could say multiple lines like this and we just put that

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with triple quotations like this.

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And lastly we can do a little bit of what is called concatenation.

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We could say something like print this string is and then we'll want to put a space at the end here

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and end the quotation that we can put a plus sign in here and we could say something like awesome and

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and that parentheses so with all of this you're going to see that OK we can print Hello World.

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It should print Hello World hello world.

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This string runs multiple lines and this string is awesome and it should be space.

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Awesome here because we included the space.

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Now you're going to notice even though we've put line breaks in for us no line breaks are going to be

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printed.

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We'll talk about that here in one second.

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So let's save this and let's just run it.

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So we're gonna go ahead and run Python 3.

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First up Pi.

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And everything looks as anticipated right.

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So I want to show you one thing.

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Let's tab up twice and let's put an ampersand at the end of this.

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Watch what this does.

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Now we have access not only to our script here but we can also run code as well.

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So as long as we save this we can run the code and we don't have to keep exiting out back and forth.

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So let's say that we did want to put a line in between these two Hello worlds.

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We've got this here what we can do is we can print this can say something like a

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and like this like a type today and we close this off and you can put a little note next to it say you

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remember and just say new line.

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So when you have that backslash n that prints out a new line.

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So let's say that and just take a look at that and there you go.

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You have a new line put in there so quick and easy way to add a line in a line break.

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And.

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So here.

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Very simple very simple lesson right.

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All we're doing is just learning how to print things.

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And we're dealing with string so even if you want to go in and build upon this you can add comments

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in for yourself to make this easier.

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So you can come in here and say double quotes you could say single quotes and then you can come in here

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and say triple closed for multiplying.

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Right.

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And this way you know kind of what everything is doing.

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This one you can say here you could say we can also can cat in name.

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I don't know if he spelled that correctly but I'm hoping I did.

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So that's really it for this lesson.

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Just want to cover the basics.

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So in the next lesson we're going to start talking about math and the math that python can do and again

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where does it continue to build upon this.

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So I'll catch you over in the next lesson.