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Hi, guys, and welcome back.

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In this video, we're going to learn

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about the in keyword in Python.

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The in keyword is something we can use

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to check for membership,

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whether one thing is inside a list

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or a tuple or a set.

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Let's get started.

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I'll have a list of friends,

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which contains Rolf, Bob, and Jen.

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And then we can very easily print

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whether Jen is in friends.

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And this is going to check whether the string Jen

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is one of the members in this list.

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So if we save that and run it,

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you'll see that we get back true.

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Now let's say that we have a set

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of the movies we've recently watched.

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I'm using a set here

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because movies are unique, so you can't have duplicates

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and having a set actually helps you prevent duplication.

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In addition, the movies that we've watched

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in this case don't have any specific order.

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So we don't care about the order,

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and therefore a set is a perfect structure

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to put these movies into.

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Then we are going to ask the user

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for a movie they've watched recently.

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And finally, we're going to print

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whether that movie is in our movies watched.

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If we run this,

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then you'll see that if we type The Matrix, you get true,

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but if you type Monty Python,

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then you'll get false.

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The in keyword works in sequences

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like lists, tuples, sets.

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It also works in strings, actually,

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so you can check whether a string

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is inside another string, such as a substring.

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For example, R-I-X would be in The Matrix.

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So you can do checks like that, as well, if you want.

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Let's move on to the next video

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where we're gonna learn how to use if statements

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with this syntax here

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so that we can create even more powerful programmes.

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I'll see you there.