Loops |Section 4|Celestial Warrior

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Hey, in this lecture you'll learn about loops

and loops are very important.

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They are one of the fundamental building

blocks of the Python programming language

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and of every other programming language

as well because loops are crucial.

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So what are loops? Well loops are basically

the way that allows you to execute the

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statement multiple times, so what does

that mean? Let's say you have a bunch of

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files, text files and you want to insert

a certain string inside each of these

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text files, so you'd have to open those

text files in Python by writing the

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Python code that corresponds to opening

a file and then you insert that string

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inside the file and close the file and

save it, so there is some code that does

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this opening and inserting the text and

closing the file and if you had 100

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files you'd have to execute that code

100 times so you'd come up with let's

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say 100 lines of code but that doesn't

sound very efficient so that's what loops

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are for. So a productive way to solve the

problem that I just mentioned would be

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to create a list of these files so

Python lists all of the file names and

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then you would use a loop to iterate

through this list of file names and a loop

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would do all that in just a few lines of

code and there are two kinds of loops in

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Python, there is a for loop and a problem

for example that I just mentioned would

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be solved using a for loop and we also

have the while loop. A while loop does

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also repeatedly execute a statement

that you give, that you write and it

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executes it as long as the given conditional

true, so let's say you have a user that

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is trying to login in your web app and

while he keeps entering their own

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password, you'd continue executing a

statement that would reject his login to

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your system, so while the password is

wrong reject the user, something like that.

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So that's about the definition of

the for loop and the while loop. In our

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next lecture I'll show you the syntax of

the for loop and by also looking at an example,

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so see you in the next lecture.

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