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-: By the way

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there is actually one more way that we've actually seen

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in lists how to look for an item in a dictionary.

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Remember how in lists we use the keyword, "in."

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We said something along the lines of,

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hey, is i in a list

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that contains i?

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Or we even use a string like, hi.

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Well, you can do the same with dictionaries.

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I can say, does basket exist in user?

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And let's print this out,

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and run.

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And it's going to say, yep, basket does exist in user.

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What about,

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what about size?

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Does that exist?

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Nope, that's false.

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That does not exist in user.

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But here is where it gets really interesting.

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And this, again,

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is another dictionary method that we can use.

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And by the way, you can see that there's not

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that many dictionary methods that, well, dictionaries have.

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Luckily we're going to go over the main ones here.

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The one is called "keys",

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and keys simply checks the keys.

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What are the keys of user?

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So if I go, hello here, and I click run,

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well, no, keys are sorry on this side, not this.

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So this is a value.

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So if I want to check keys, I'd say age.

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Which is true.

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But if I want to check values, well, in that case

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if I do, hello, I get true.

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It's going to go over

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or what we call iterate over the values.

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Another one that's really useful is the items.

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And items is special because we've seen keys and values

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but items actually grabs the entire item.

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So the way we can actually see this is

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let's just remove

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and click run.

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Alright, this is interesting.

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I have dict items here and I grab, looks like a list.

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And in here we have a bracket basket

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1, 2, 3, greet, hello, and age 20.

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But there's some weird syntax here

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that we haven't seen before, and this is actually a couple.

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So we're going to hold off on this and talk

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about this a little bit more when we talk

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about our next data structure.

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But keys, values, and items, is an easy way

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for us to grab these things for us from our dictionary.

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Let's continue on

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with other dictionary methods that we might use.

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One is a very nice one, it's called, "clear."

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And if I run this,

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you see that I get an empty dictionary.

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What if I just run users dot clear here and run user?

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Well, it's still an empty object

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or an empty dictionary.

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So you can see here that clear doesn't actually

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return anything.

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It doesn't, well, it's just in place,

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removes whatever the dictionary has.

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So it just creates an empty dictionary.

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What about copy?

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Well, a copy allows us to copy a user

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so that if I print user

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and user two

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and I click run.

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I get two users each keys and values copied.

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But if I now,

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let's say clear the first user

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and I click run,

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the first user is empty

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but because I've copied the second user,

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the second user has the old information.

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And this is a concept that we've talked about before.

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Another useful command

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and let's just go back to having user,

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is user dot pop

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which removes a key and a value from the dictionary.

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So in our case,

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let's just say we want to remove the key that is age.

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So I'm going to say age, and if I run this,

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I get 20

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because pop returns the value of whatever got removed.

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But if I do print user now, you'll see that age does not

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exist anymore because we've popped it off.

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But pop, as you can see, removes the actual value,

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or returns the actual value, 20.

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Here's another really fun one, pop item.

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And honestly, this I haven't used much,

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but I just think it's a fun one.

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Pop item, if you guessed, well, you're not going to guess.

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Oh, and that's because

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I have to make sure I write it

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properly with lowercase.

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If I run this,

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which just happened.

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It randomly pops off something.

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One of the keys and the values.

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In this case, age 20 is removed.

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So the last item on the dictionary gets removed.

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But remember, a dictionary is an order.

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So if this was a massive, massive dictionary

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that, well, doesn't have any order to it,

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sometimes it removes some pair.

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As you can see, not the last one,

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but some pair of key value.

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So you have to be careful with this one.

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It doesn't necessarily just remove the last thing

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that you entered, but it might be useful on some occasions.

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Finally, we have something called, "update."

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And update simply updates,

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as the name suggests, a key value.

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So let's have a look here.

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All we have to do is give it a new dictionary.

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So curly brackets, and just simply say,

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hey I want to update age to 55.

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If I click run,

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oh, and I forgot a bracket here.

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Let's try that again.

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If I click run,

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there you go.

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Age got updated.

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But if this was a key that doesn't exist like ages

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and I click run, it will still update with a new key item.

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So this is another really useful method.

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Alright, that's it for dictionaries.

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I'll see you in the next video.