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Welcome back, everyone, to this lecture, we're going to be discussing Tuples and Boyens.

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Tuples are similar to lists, except for the fact that they are immutable.

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That means they can't be changed or mutated, so immutability means you can't go in and swap out an

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item that's already in that tuple.

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So tuples are still a sequence just like a list, but you can't change them now due to the immutability.

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That means they're going to have less methods than lists, and they're used when you don't expect or

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want a particular user to be able to change the sequence of items.

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While we don't manually define tuples, often we do see many Python functions actually return tuples

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when returning results recall, we call these items method on a dictionary and actually return tuples

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of key value pairs.

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Add the key first and then the value.

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This is a great use case for a tuple because you want to make sure that the user can't accidentally

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swap the value and the key confusing which one is which because it's in a tuple and it's immutable.

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You're always going to know, OK, that first item is key.

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That's second item is the value.

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Billions are going to be our basic building block for logic and control flow, allowing us to indicate

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if something is true or false.

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Let's explore these concepts in Python.

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OK, here we are inside the Python file.

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What I want to do is simply create a tuple if you want to create a list.

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Remember, that was square brackets like one two three.

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And those are the items in the list for a tuple.

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We'll say my tuple.

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This is similar to a list, except you use parentheses.

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So still, the same different types of items can go in there and then we can go ahead and print out

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my tuple.

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Save that change.

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Go ahead and run this.

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And now I see the tuple.

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Now look what's going to happen if I try to reassign an item in a list?

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For example, if I say my list grab item index zero and say it's equal to new and let's go ahead and

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then print out my list.

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Save that change.

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No, I'm still printing out the tuple as well.

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If I run that now, I see new two three and then one two three.

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So what's actually happening here?

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I'm just grabbing the item at index zero and this list and reassigning it to be new.

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No problem for a list.

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Now let's try the same thing for a tuple.

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So I'm going to switch this out to now say my tuple grab item at index zero and try to set it equal

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to new save that chains.

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Go ahead and run this.

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And now you get this error message, so it says sorry tuple object does not support item assignment.

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So as we mentioned, tuples are immutable, so once it's set to one two three, that's it.

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You can't go in and swap another item out.

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So you're going to want to use tuples when you don't want any user to have the ability to swap in items,

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which is why we see it so often used as a return mechanism or just a good way to report values back

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to a user.

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You say, here's a tuple, I'm not going to allow you to change it that way.

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We can avoid confusion later on.

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OK.

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So again, things like actual indexing is totally fine.

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So if you want to actually know the first item in a tuple like, say, index zero, that's totally OK.

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You just simply say Python Example pie here and notice it reports back.

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OK, item one is at index zero.

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Inside this tuple?

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No problem.

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Well, we can't do.

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Is the reassignment now.

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Again, as I mentioned, there's not going to be as many methods available on a tuple.

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I just want you to get familiar with the fact that parentheses are going to distinguish a tuple and

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a tuple is still a sequence of items.

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All right.

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So that is a tuple.

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The other data type I want you to be familiar with right now is a Boolean, which you may have heard

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in other languages.

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A Boolean is essentially just a true or false.

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For example, you can say a is true and then you can print out a.

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Save run that and you can see true, the other type of bullying is false.

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So that's pretty much it.

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It's either true or it's false.

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And there's not a whole lot we can do with them right now.

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But later on, when we learn about control flow, things like if statements, this is where you begin

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to add logic to your code.

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Things like, OK, if this is true, then do something else or if this is false.

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Go ahead and do something.

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And for instance, you're going to see these kind of things and we learn about comparison operators,

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for example.

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I'm not saying, OK, Prince is one greater than two.

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So this is actually a comparison operation.

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I'm saying compare one.

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Is it greater than two?

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So let's go ahead and save that and see the result.

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This returns back a boolean false.

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Now, let's say, is one less than to save that change.

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Go ahead and run this and this returns back.

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True.

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So we can already see that there's some idea of comparing two different data types within Python to

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get back a boolean true or false.

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Now that's it.

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Just very brief overview of Tuples and Bulletin's.

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We'll be using those later on in our code.

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OK.

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Thanks.

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And I'll see you at the next lecture.