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I want to address a question that you may or may not have but it's something that's taken me years to

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understand and that is why not just have everything as global variables.

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I mean all this confusion of who has access to who.

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How easy would it be if everything was just on the main page.

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All our information all the data on our global scope so that everything has access to everything.

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Wouldn't that be easier and you'd be kind of right.

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I mean that would make all this headache go away.

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Right.

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But you have to remember that machines don't have infinite power don't have infinite CPR you don't have

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infinite memory they all have limited resources.

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And as programmers we have to be conscious of what resources we use because sometimes that can cost

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us money.

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Sometimes that can crash our computers and scope is a great demonstration of this.

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For example this code right here when this function is run we're creating technically just one location

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in memory for the x variable.

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So we have that bookshelf in our computer that is X. That's pointing to local when we actually call

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this function.

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And then when we say non-local here Well we're saying just don't create another bookshelf for us.

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Just use the one that we already have and assign it non-local if we didn't have this line by the time

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we get to line seven.

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We've placed in memory x equals two local and x equals two non-local.

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So we have two locations now in memory.

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Now this isn't a big deal because well in this day and age we do have a lot of memory but as programs

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get larger and larger this does become a bit of a problem.

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OK.

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But what about a function.

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I mean we learned that functions allow us to not repeat ourselves and being able to call out our multiple

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times.

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But another good use of functions is that once we call this function and all of this is done the computer

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and the Python interpreter specifically destroys all this memory that is once we finish with the outer

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function.

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I can't really call print x here.

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It's going to give me an error.

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It's going to say I have no idea what X is and why is that it's because after we call this function

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the python will be called the garbage collector is going to say hey it looks like we're done with this

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function.

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And I see that this x variable well in this x variable we're not gonna use because we're done with this

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function.

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So I'm going to collect that garbage and then just throw it out.

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So I'm going to empty that memory cupboard so that other resources or other programs can use that.

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And that is a really nice feature where python just automatically removes these for you so that you

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don't clog up the computer's memory and that's why scope is useful.

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We don't have to think about it in such detail like I've mentioned it but it's nice to know that it's

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there so that your programs don't hog up a lot of memory and they can run efficiently.

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This is a bit of an advance topic but I did want to include it in here so that you can think about why

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programs are designed the way they are.

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All right let's stop talking now.

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I'll see you in the next video by.