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Okay, let's take a look at these things called tuples,

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or some people call them tuples.

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I actually don't know which is the right way,

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tuple, tuple. You can say it either way, I guess.

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So a tuple in Python is basically a list, but it cannot be

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changed. So a little while ago we saw a list is equal to

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'[1, 2, 3, 4]', and we could print the list, and then we could do

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'lst.append', and we could put 5 in there,

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and then we could print that list, and we see that we added something

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just like this, '[1, 2, 3, 4]', '[1, 2, 3, 4, 5]'.

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But a tuple does not work that way.

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A tuple, it cannot be modified.

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This is really good for performance increases, but it's also

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really, really good just for keeping your data the same.

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Some things just don't need to change.

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So for instance, let's say I have a tuple, and you open it,

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and close it with a regular set of parentheses here.

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And let's do '('Kalob', 'Henry', 'Zephyr')'

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And this is not going to be called 'tup'.

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This is going to be called a 'group'.

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So it's me and my two cats.

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Now, on some instances of Python I have noticed that Python

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will get this confused for a function.

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I don't know why that happens, but if that does ever happen

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to you, you can just throw a comma at the end here,

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and that comma with the closing parentheses, Python goes,

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"Oh, I know that's not a function.

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There's nothing there. That's got to be a tuple".

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So we have this 'group', and in this 'group', let's say we wanted to

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add a new person to this 'group'.

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Well, let's hit '.', and then tab, and we see that we don't

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have 'append' in there.

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We have 'count' and 'index', but we don't have 'append'.

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So let's go ahead and try this

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anyways, 'append', a new pet called "Axel", I guess. "AttributeError:

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object has no attribute 'append'."

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It simply does not exist.

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We cannot do anything with that.

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It does have 'count', which is pretty cool.

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So I could count the number of times "Kalob" shows up.

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It shows up once.

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I'll also show the number of times "Henry" shows up, which is also once.

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And we can actually change this as well.

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So let's put "Henry" in here just to show the 'count' example.

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We've got "Henry" in here twice.

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I just reran those cells.

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And so it's '('Kalob', 'Henry', 'Zephyr', 'Henry')' now.

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'group.append' still doesn't work. Down here,

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'group.count(

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"Henry")', now shows up as two.

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Now, one thing to keep in mind here, is with lists and tuples, they

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do not have to be unique items.

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We'll talk about sets a little bit later where every item

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is going to be unique.

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But that's not the case here.

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So effectively we are stuck with '(Kalob', 'Henry', 'Zephyr', 'Henry')'.

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And let's say we wanted to get rid of "Henry".

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How do we get rid of this?

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Well, with a list, we simply did the list name or the variable name, '.remove',

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and let's do "Henry". Oh, that doesn't work.

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Let's do another example here where instead of running 'remove',

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we run 'pop'.

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Oh, we can't even get rid of that.

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So what do we do?

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The only other option we have here is we can create a new

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tuple. So let's call this 'new_group', and we are going to

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say 'group', and we're going to slice this.

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We're going to start at number 0,

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this is an index.

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So 0-1-2, and we want to go up to number 3, but not include number 3.

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So 0-1-2-3 not including 3.

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[no audio]

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And let's do this, 'new_group', and we have removed it.

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But we've also created a new variable.

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So now we have two variables with basically the same data

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in it, and we're no longer being very efficient.

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Now, as an example of how a tuple is a sequence, we can use

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a for loop. So 'for item in new_group', because we don't want

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the old 'group' anymore, 'print(item)'.

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Now, that 'item' is going to be "Kalob", "Henry", and "Zephyr", in that

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order, and a tuple will always maintain that order.

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Other data types do not necessarily do that.

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Lists do, strings do, and tuples do.

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They will maintain their order.

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Sets do not, and dictionaries are not always guaranteed to

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maintain their order, depending on the version of Python you're using.

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But when it comes to a data type like a tuple, once it is

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set, it is set in stone, and the only way to get rid of it

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is to delete it. So we could do 'del group'.

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And if we do 'group', we're going to see an error.

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'group is not defined' anymore, because we deleted it.

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So that is a tuple.

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A tuple is a lot like a list, but it cannot be changed.

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It is completely immutable.

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It's that word here.

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I did not mean for that to execute, but it is completely

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immutable, which means once you set your data in here, you

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set those items, they are set in stone.

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There are ways around that by creating a new variable and

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deleting the old one,

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but at that point, you're still not being very efficient at all.

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And it sort of defeats the purpose of using a tuple.

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If you need to actually modify your tuple at all, you're

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probably better off using a list.

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But in Python, tuples have their place, and it is good to

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know how they look and how they act.

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And the fact that you can't really do too much with a tuple

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is actually pretty nice

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sometimes. Sometimes you want that data integrity.

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Go ahead and give this a shot.

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Create a tuple.

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Where do we have a tuple? Tuple-Tuple-Tuple.

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'group = ('Kalob', 'Henry', 'Zephyr', 'Henry')'.

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Create your own tuple, and then just print that out,

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and then what I would like you to do is try to run '.append'

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as well as '.remove', and you should see an 'AttributeError' for both of those.

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If you see those errors, you're doing the right thing. That's okay.

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Errors are okay to have. Once you see those 'AttributeError',

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let's head on over to that next lesson where we learn about

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sets, I believe is the next one where it's a lot like a list

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and a tuple, but it's totally unique and doesn't always maintain its

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order. So have fun with this.

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And let's head on over to that next lesson whenever you're ready.