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And before we continue, one thing to know is to

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know how to iterate on list with loops. So you

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can perform a set of instructions for each element

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on the list. And I'm going to show you this now,

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because simply, you're going to use this multiple

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times in every project you create in the future.

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Okay, so I'm not going to introduce any new

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concepts to you now. We are just going to use

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what we saw previously. And let's get started with

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an example. And I'm going simply to comment this,

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okay, so we don't use it, I can remove it, I could

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comment it, if you want to comment, you can go on

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Code, Comment with Line Comments here, and you

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have the shortcut if you want. Alright, so now the

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program basically has nothing in it. I'm going to

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create a number_list. Okay, let's see 3, 5, 8, 12, -3,

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-7. Okay. And then I'm going to do

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for number in number_list. And I'm going to print

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number. This is going to go through all the

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elements of the lists. And every time we enter the

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for loop, the number variable here will contain

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the next element on the list. And we can actually

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use that to do anything we want here. As you can

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see, that is quite similar with this, okay, we

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have for i in range(10), range(10) is actually a

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list between zero and nine. So we have the same

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thing here for, we just don't use i as an index.

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Okay, as a counter, we use a no meaningful name

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here because we have a number_list. So if we have

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a number_list, we're going to use a number, okay.

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Because why do we have a number_list we have

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numbers. for number in number_list, print number.

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Let's run that. And you can see we print all the

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elements, okay, in the list. Now you can do for

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example, if number is lower, strictly lower than

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zero, let's say print number is negative. You

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could also add an else to say the number is

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positive, let's run that. So you can see we have

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3, 5, 8, 12, -3, and the number is negative,

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-7, number is negative. Okay, just to show

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you that you can combine conditions and loops,

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okay. Also, you can use an if inside of for,

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you could use another for inside that if or a

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while or whatever you want. Okay, so you can

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combine them between each other. And well this as

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you can see, this is very convenient way to go

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through an lists. Okay, and to recap, as you can

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see, combining a for loop here with a list is an

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extremely powerful combination. You just need one

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line of code to do that here. And then you can

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write a block of instructions to apply for each

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element on the list. And this you're going to use

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it quite often in all your future programs.