Original subtitles

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Hi, in this lecture you're going to learn

about variables. So what is a variable?

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Well a variable is like a container

where you can store various data types

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in Python for instance this program now

this doesn't have any variable in it for

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now, so let me try and execute it and

you'll see that this prints out of the

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hello string. String is a data type, but

we'll cover that later. Now what is the

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variable? Well and variables will keep

your code more organized. Let me create a

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variable here, greeting so you can call

your variables whatever you like you can

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give them any name however there are

some naming rules which I'll mention in

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just a bit, so let me create this

variable for now. I'll store in this

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variable, I said variables are like

containers so I'll store this text in the

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variable greeting and then what I do is

instead of doing print hello I'll do

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print greeting and save the script ctrl

s and then go through the command line,

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the upper arrow key, enter to execute and

you get the same output. So this is how

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you create a variable you don't use any

quotes because when you use quotes you

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are creating a string data type not a

variable and you can also use a dash

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before the variable that would also be

fine so you get the output correctly

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but you cannot use numbers before the

variable ctrl s to save, execute and get

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an invalid syntax, so this syntax is not

valid in Python, but you can use numbers

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after or between the variable name let's

say here greeting2. So that would

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be fine to use so that's the condition

about naming

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your variables, you can start them with a

letter or a, or an underscore. Now if

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you're not experienced with programming

you may still be confused on why do we

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use these variables? Well this is a very

simple program, actually very useless, but

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normally your programs will interact

with your users. That is what we call a

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real program. You create a program to

give it to people so they can interact

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with the program they can generate all

different outputs and so on, so let's go

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Ahead and make this program more dynamic, so

what I'll do here is I'll get the text

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from the user interactively. To do that

you need to use the input function, this

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is also a Python function and inside

the function you can enter a message to the

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user so let's say write a greeting.

A column and make some space there and then

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you print greeting2, save the script.

Execute and now the program is asking

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us to enter some input so let's go ahead

and say hi this time and we get the output

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Printed out in here, hi, so what

happened here is we created a variable

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and that variable will store the value

that the user submits in the command line

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here, in the terminal so the user

submitted the hi text and this text will be

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stored in this variable so as I said

variables are like containers and then can

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use this text in various ways, but in

this scenario I'm just passing it to the

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print function, so I want to print it out

on the terminal here and the print

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function will get the value that is

stored in the greeting2 variable and

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print it out on the terminal. That's it.

And yeah, I'd like to close this lecture

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now and I'll see you in the next lecture.