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Instructor: Welcome back.

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Let's try a simple exercise.

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I want you to build a simple counter.

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And this counter is going to count the items in our list.

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What does that mean?

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Well, let's say I have a list,

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and this is a reserved word.

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Remember, it's an actual word in Python.

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So let's name it my_list as a variable.

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and this list has 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

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What I want you to do is using looping

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to loop over this iterable list

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and sum up the total of the list.

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Pause the video if you need to.

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Otherwise, let's see how we can do that.

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What I'll do is create a counter variable

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that will equal to 0 to start off with,

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and then I'll say for item in my_list,

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I'm going to

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counter = counter + item,

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and then at the end,

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I'm going to print counter.

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Let's see if this works.

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I'm going to hit run

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and I get 55,

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which, if my quick math is right,

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should be correct.

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Now, when doing this exercise,

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you may have gotten tripped up a bit.

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So let's think about this.

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Some of you may have made an error

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where you did the print here.

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But if you did the print here,

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you remember that it's going to get looped over.

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It's part of this code block,

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because of the indentation,

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and it's going to print as many times as there are items.

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So you have to make sure

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that the indentation is like this

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so that you get the total.

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The other thing that you noticed

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is that in order for you to keep a counter

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or a total of all these items,

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you had to make sure that you had a variable

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outside of the loop,

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because the loop runs the code over and over,

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and you needed something on the outside

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that doesn't change.

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Because if you moved the counter to 0 here,

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well, every time the counter will be reset to 0

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so that by the time we get to 10,

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counter will be 0,

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so you get 0 plus 10, which equals 10.

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And then you'd get, well, 10.

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So you have to be careful here

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that the indentation is an indication of us looping.

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And when you loop something

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and you wanna keep a tally or total of something,

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that you have these issues

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of making sure that what you wanna loop over

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is inside of this code block.

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But what you don't want to,

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if you wanna have some sort of information

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that's outside of this loop,

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then you keep it like this.

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If you weren't tricked by this question,

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good job.

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If you were, don't worry.

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It's all part of learning.

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I'll see you in the next one.

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Bye-bye.