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In this lecture, I'm going to talk about the three types of sequences that are available in Python

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sequences, done types that allow you to store multiple items under the same variable name and Python,

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both see Python and Micro Python provided three types of sequences.

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We have lists, tables and ranges in this lecture.

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I'll show you how to use all three in a basic way so that you are prepared to use them in the lectures

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that are coming up later in this course.

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Let's begin with lists.

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So lists are mutable sequences.

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Mutable means that once you create a list, you can change it later.

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You can edit individual items in a list and typically we use them to store items that are all of the

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same kind.

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So you can have a list, for example, that store integers or a list that contains floating point numbers

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or strings.

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Tuples, on the other hand, are immutable.

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There are still sequences we can store multiple items in a temple, but unlike a list, you can't make

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a change to a tuple once you create it again.

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Unlike a list, though, in a table, typically you can store data items of different types.

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So you can have a table that contains numbers and strings.

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No problem at all.

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Finally, Rangers' is a type of sequence that contains numbers and just like a tuple, it is immutable

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and we use ranges to count in loops.

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For example, is the most common case use for a range.

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So let's have a look at some examples.

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And these examples, again, are borrowed from the documentation, which is where you can go to do more

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reading about each one of those.

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So is the invitation for lists.

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These are the documentation for tables.

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And finally, you've got the range function here that we use to generate range sequences.

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All right.

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So let's begin with lists to create a list.

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Just going to copy so that if there save myself from typing and making typing mistakes.

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So this is how you can quickly create other ways as well, as you can see in the documentation.

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But in most cases will be creating a list like this is a variable name is always the assignment operator.

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And then we've got the square brackets that contain the items that we are storing in a list.

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In this case, as you can see, we've got a list of strings.

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We submit this command and now we have a list.

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We can have a look at the contents of the list by just calling its name.

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And you can see again is denoted by the open and closed square brackets and then the items inside the

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list.

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I can have a list of integers, for example, in TS, and it's exactly the same way, except that now

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we've got the numbers.

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Let's make it four.

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And here's the list tab for code completion.

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And these are the integers.

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We can also do things such as list the integers in reverse order.

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So let's say a list of letters and I can say that give me a list that is sorted in reverse, reverse

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order.

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And it would look like this just printed out now.

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So internally, Python has rearranged the items in this list of letters and now can print it out.

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And you can see that it's printed out in reverse order.

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You can find more information about this and the various methods that are available here.

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I'm taking some examples out of this documentation and also show you one more place.

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So the conclusion that shows the functions that are available for a list in the Python three library

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standard types documentation, then you can see that this is one of the example operators that he can

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use of functions.

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And the one that I've used is stored and I turned reverse into true so I can give me the listing or

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items of the list in reverse order.

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I can do the same thing for the numbers.

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Of course I can say list.

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Of integers and just a short reverse order like this, and now the numbers come out from top to bottom

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review, highest and lowest.

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I can also retrieve individual items out of a list by using the square bracket notation.

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So, for example, if I want to see the second item in this list, which is index zero and one, then

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I can call that like this list of letters, open square bracket index one and close the parentheses.

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And that will give me a.

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So this is the second item in this area, you can click on the area as well, and the object inspector

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will also give you an index number and the value stored at that index number for go for the same thing.

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But now index to as you see here, that's a and most getting a ratio in the exact same thing happens

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with the list of the numbers and lets you do that exercise or least clear up and move on to tuples and

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to create a tuple just copy and paste the table that I've already created here.

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And you can see that I'm using the same method, essentially, as with every variable of the name of

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the variable, the assignment operator.

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But now instead of square brackets that I'm using for the lists, I'm using a parentheses, open and

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close parentheses.

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And inside, as far as the items of the table are concerned, you can see heterogeneous items.

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I'm using integers and strings, floating point numbers, and that is no problem at all for a tuple

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I can.

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Print out the contents of the table like this on the show, and you can see that it comes back with

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the parentheses instead of the square brackets.

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And that's how, you know, whether you're working with a table or with a list is by looking at the

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types of brackets that are used, whether they are parentheses or square brackets, in order to retrieve

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an item from a table and using the same notation as I did earlier with the list.

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And I'm going to use this time square brackets.

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So this is the thing that sometimes can be confusing.

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So, for example, if I want to print out, just going to click on the table, go and it appears on

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the inspector I to print out the let's say the.

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Item number one, index number one from the tuple, then I use the square bracket to indicate that and

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hit enter and I'm getting a fair go for.

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Indexed to that will give me the number to out, since that's what's stored in index to there's more

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documentation about how those here in Python, three libraries, standard types, and you can see more

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information about how to use tuples here.

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All right.

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Now, the last one that I want to show you is the range.

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So the range to said we use that there's a function called range that creates a sequence of numbers

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and the documentation for the range of the leadership right here in this tab.

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So here's some examples of how you can use it to the function range if it requires at least one parameter.

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But you can have more than one error in this example here has got two parameters and there's one more

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down here.

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Believe it's not listed here.

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I'm going to give you an example.

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We can have three parameters, but the source documentation and you can look at it right here, we can

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see the range function and there are three parameters that is capable of receiving as a start stop.

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And then if you want, you can define a step which can be negative or positive.

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So let's have a look at a few examples here of how to use ranges.

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So first of all, I'm is going to create a simple range.

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It's a sequence of numbers that count from zero to one.

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Let's check it out.

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Check out its contents.

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That is, you can see zero to 10.

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And if I click on the object inspector, that's what comes up right here for use the list command and

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ask Python to list the contents of this variable range zero to 10.

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Then you'll see the actual components of this range.

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You can see called square brackets, which means that there is a list in the square.

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I was able to use the list command to show me the actual items in this list.

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So the thing to take away from this is that the range function allows us to quickly create lists of

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numbers.

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So if you just use a single parameter, then the list of numbers that you get starts from zero and goes

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all the way to the number just before the number that you have specified in the function.

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So it's zero indexed and therefore is going to go up to nine.

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The variation is to have a list such as this where we use the range function, but now we got the two

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parameters.

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The first number is the starting number and then we got the last number.

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But the ending number.

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And if you use the list function to check the contents of this list, you'll see that it starts from

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five inclusive and goes to nine not inclusive.

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The last variation of the range function that I want to show you is the one that used this, the third

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parameter for the step.

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So in this case, we've got range zero to 50, step five.

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It's going to create a list that starts from zero finishes at forty nine, but count at five point thirty

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five.

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That will look like this.

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This range.

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All right.

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Zero, five, 10, 15 and so on, up to forty five.

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You can also go negative.

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So I'm going to go to modify this is going to be from 50 to zero, Steph, minus five and five.

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Use a minus sign here.

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So there's going to be five zero and minus five.

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And let's give a list to this range, 50 to zero.

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And it looks like this.

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So counting down of it can go down to negative numbers.

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Maybe.

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Let's try this.

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Let's go up to minus 10.

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You saw the mistake here that should be minus 10 and.

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Let's make that 10:00 for the new range and let's print it out.

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We can have negative numbers, so all this is going to be very useful.

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You can see in.

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This example here where we can use the range inside a full loop in order to create this loop based on

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this range is something that will be using quite frequently in the lectures that are coming up.

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OK, so that's about the three types of sequences in.