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Welcome back.

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Let's talk about some useful tricks with lists that you'll see a lot in Python code.

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Well, one we have already seen.

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It's this idea of lenth.

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You're going to be using this a lot, that is to figure out the length of a list, which in our case

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is now seven.

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Another really useful trick is to reverse a list.

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Now, I've already showed you how to reverse a list, but sometimes you can do that with list slicing

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against something that we've seen in string slicing.

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So I can actually do BASKETT.

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And then semicolon, semicolon, negative one, if I click, run here.

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Is that what you expected?

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Let's go through this line by line.

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I've sorted the basket so that it's from a all the way to Z and then I've reversed this, so it's in

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Z all the way to A and then I've reversed the basket again so that instead of being in reverse, it's

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now in order.

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ABCDE e x.

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And this list slicing creates a new list, right, if I print basket here.

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You'll see that the basket is the reversed version, the last action that we've taken on it versus list

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slicing, that creates a new version.

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So this notation, you'll see a lot with lists when you need to reverse the list.

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Or maybe you need to make a copy of the list like this, or maybe you need a portion of the list.

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Another useful thing that you'll see a lot of is something called range.

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Let's come at this out for now.

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If I wanted to generate a list really quickly, let's say from one to one hundred, I can do something

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like this.

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I can say range and then start and then stop.

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So let's do one hundred.

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And if I print this.

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And I run, hmm, I get a range one to 100.

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But if I wrap this in a list.

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Which is going to create a new list for us and I click Run!

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Look at that, I get a range from one all the way to ninety nine, remember, it's the start and then

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whatever to stop it.

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So before it hits one hundred, it's going to stop.

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Now, if I remove this and just do one single thing.

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I get a list starting from zero all the way to 99, if I want to list that has a hundred and one items

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because it starts at zero, I would just do one hundred and one.

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And range is something we'll talk about a lot more, especially when we talk about loops in programming,

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but this is a great way of you to generate a list really, really quickly, especially a numbered list.

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Finally, the last common thing that you'll see a lot is this idea of dot join.

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What is dot join.

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Join is actually something that works on strings.

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It's a string method, but it's often used this way.

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We have an empty string.

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And this empty string, let's say, sentence.

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And then we can do sentence dot join.

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And join takes what we call an iterable, which is a list for now, and in here we can have a sentence

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like, Hi, my name.

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And now if I print sentence.

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And I click, run here, hmm, I don't get anything, let's figure out why, what if I type in an exclamation

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mark here and I click run?

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All right, it's printing out sentence, but it looks like Dudd Join creates a new item for us.

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So let's just assign that to new sentence.

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Now, if I do a new sentence and print that out.

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We see that I.

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Hi, my name is Jojo.

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So this is a little funky, right, we have these exclamation marks.

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Between our items and join Joynes, these little iterable items, these lists by whatever is in front

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of it.

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So if we actually change this to an empty string click run, we now get this.

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If I add a space in between and click run.

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We get hi, my name is Jojo.

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And sometimes you'll notice this pattern a lot, especially if you want to join and create a new string

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out of a list of items.

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Now, a shorthand way of doing this is to actually not even bother with this and just doing an empty

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string.

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Don't join and then joining all the list items.

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There we go.

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So all we're doing is combining list into a string, and this is a common pattern that you'll see a

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lot of I'll see in the next one by.