So tuples. Tuples seems like a strange name, but actually, it's a term that comes from mathematics and it means an ordered sequence of things of n elements with no negative integer within the counting starting at zero. That's going to make sense at some point in this lesson, what is exactly meant by that? Now, tuples are part of our data structure family. We're going to see a strong similarity between tuples and lists. Strong similarity, but also a strong difference between those things. On one hand, they're organized in a very similar fashion, but in other ways they're quite different. Now, I've tricked you a little bit because in fact, we have already been using tuples almost from the beginning of the course, from the first lesson. When I assign a value to a variable point in this case, so if I'm assigning, let's say a sequence of X, Y, Z variables written in this fashion, that's actually a tuple. I know it's a tuple because it's defined between parentheses. That's how we assign a tuple, is we put more than one variable separated by a comma within parentheses. That makes a tuple. Now, it doesn't have to be variables, it could be hard-coded numbers which we have been doing already quite a bit for our point values. It could also be any amount of numbers that could go on for quite a bit, all separated by commas. It could have not quite an infinite amount, but close to an infinite amount of numbers. Tuples are often called arrays. Now, I'm also not just limited to one data type and one tuple. I can put all different data types in one tuple, as long as they're separated by a comma, that's going to work just fine. Now, very important aspect of tuples is their organization. They're organized in what's called an indexical manner. What that means is that we can consider each one of these spaces that's defined both by the end parentheses, and by the comma as a slot and each one of those slots starting from left to right are numbered. Always starting with zero, accounting is at zero, starts with 0 and then 1, 2, 3, so on, depending on how many slots that I have within my tuple. Now, if I want to access just that data that's in that slot, this is how I do it. I write the name of the tuple and its index number, the index number within brackets after that name. Then that's going to, if I'm saying print, it will print that out. So the next one, 1 is 9, next one, 2 is 2.So index equally organized. Now, tuples and we'll see lists and dictionaries, as I said in the lesson on variables, is they share this exact same naming conventions. We're going to have to follow those same conventions for all those. But our analogy for variables being like a name on a file folder, that's a little space of memory that we hold some data in, we need to expand that a little bit, for tuples and we'll see ultimately in lists. We could think of a tuple instead as a n list filing cabinet and each one of those drawers of the filing cabinet has a number which is it's indexical value, and that's in ordered sequence. Then that tuple, just like a variable, has a name. We put all the different types of data in those drawers and they're stored in there, and then when we give the index number and the tuple name, we can access them. Now, tuples are what's called immutable, which is a fancy name for just saying we can't change them, we can't change the data that's in them. The only way to change the data that's in them is just like with variables, I have to override it. This is an example just like I showed with variables, where there is an assignment and then I'm printing out what's in point, just here, and then I just reassign it and then it's totally overridden with new data. One thing I can do that's probably different than a variable since I'm dealing with different pieces of data, is that I have to rewrite it altogether, but I could just replace one thing within one slot. In this case, with a variable that's holding a piece of data, zero. Then when I printed that out, that's going to print out that new zero, but I can only do that through overriding the entire tuple. That's it for tuples. That's about it. As I said, we've already been using them and we're going to continue to use them. They're very useful particularly with things like points, which we do quite a bit within this course. Next, we're going to talk about lists.