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In Python, you are going to see two primary ways in which

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you can change data.

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One is called a function, and one is called a method.

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Now, in Python, most things are considered an object, saying

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that as an 'Object'.

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Now, for now, and for a little while, this is going to be

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a little bit of I don't really know how else to explain it,

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but it's going to be a useless word to you while you're learning

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about them, because an object in English, at least, is just a thing.

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It's any physical thing, really.

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And so if we did something like 'name = "Zephyr'",

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that's one of my cats,

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This name,

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if we did type 'name', is a string.

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But let's go ahead and put this into our Python interpreter

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from our command line.

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So I'll just type 'python', get in here,

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and let's say 'name =', no let's do the other cat,

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"Henry". Then I do 'type(name)',

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we can actually see that it's a class.

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It's a string, just like what we saw here,

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but it's a class.

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And with a class comes this thing called a method.

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Now a method is a lot like a function,

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just the way that you call it is a little bit different.

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So a function looks like 'print'.

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We put stuff in here.

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That's a function because it has a function name, then parentheses,

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and then it takes our arguments in here.

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So in this case we could say stuff in here.

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We could put a comma, we could put another argument in here, another

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parameter, more stuff in here, and we could run this, and

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it runs both of them together.

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And that's because it's one function that takes one or more

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arguments. Occasionally

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these are also called parameters.

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We've also used 'type', which we already used in this lesson as well.

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And you put in some sort of variable name, and it gives you

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exactly what that function is.

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And I think I just said function, but what I meant was the

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variable, it tells you what the variable is.

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So you say 'type(name)', get 'str'.

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You say 'print("Stuff in here", "More stuff in here")', and it's

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going to say, "Stuff in hear More stuff in here".

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But because 'name' is a class, and we can see that in our proper

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Python interactive shell

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in here, it's a class.

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Now, classes have these kinds of functions as well, and behind

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the scenes they look almost identical to writing a normal

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function. However, the way we call them is different.

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So 'name' we know is a string. It's a class.

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If I hit '.', and then tab, you can see all the different

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things that I can do with it.

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I can check to see if it's a digit,

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is it a decimal,

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is it lower?

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So this is just checking a bunch of stuff in here, but we

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can also, we can split it multiple lines.

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There's a lot of things we can do.

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Let's do 'upper'.

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And all this is going to do is take 'Z-e-p-h-y-r', and turn it all

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into uppercase.

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And that's it.

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So the difference here, is with a function, you're giving

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it an explicit parameter or multiple parameters.

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With an object, our 'name' is being an object because it's a class,

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think of classes as objects,

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it already knows what that 'name' is.

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That name is 'Zephyr'.

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And so in order to make that upper case, you can say 'name',

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which Python then points to "Zephyr", make it uppercase,

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and that's exactly what it does.

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So this one is called a method.

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When it's attached to an object, when a particular function

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is attached or pre-attached to any sort of object, like a

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string, like our 'name' here,

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then we call it a method, and it gets called with '.', and

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then the method name, and then parentheses.

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Now in the title here it's called 'String Properties and Methods'.

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We now know what a method is.

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Let's go ahead and take a look at a property.

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A property.

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So a property is a lot like a regular variable, like what

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we defined up here, but it exists inside of an object.

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For example, 'name' is "Zephyr".

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How many letters is that?

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Well, it's easy enough for us to count, there's six letters in there.

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So if we said, "Hey, Python, tell us how many letters there are?"

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It should return just the number 6.

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And we can find that out by doing 'len', short for length, and

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putting the 'name' in here.

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Now we actually had to call a function, not a method, to

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get this, because somewhere inside of this object, inside

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of this 'name' called "Zephyr", Python said, "I know that there's

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a Z-e-p-h-y-r, and that there are, in fact, 6 characters in there".

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And it keeps track of that for us.

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And so that is what a property is.

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It's just a variable inside of it.

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So you can sort of think about it this way, and maybe I can

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do this in Markdown, is we have this variable called

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'name = "Zephyr"'.

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And then behind the scenes we have things like the total

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number of letters is equal to 6.

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And then we also have functions behind here, such as 'upper',

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and that's just going to take whatever this value is here,

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and it's going to make it all uppercase for us.

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So it'll say, "ZEPHYR", something like that, and so you can sort

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of think about it this way, is "Zephyr' has 'total_letters'. Behind the scenes

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Python keeps track of it, and it's not just with length or

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upper, there's a lot of other ones in there as well.

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So when it comes to objects, really, you can type in any

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sort of variable name, hit '.', and then tab, and you can

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see what else is in here.

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So let's say, does it end,

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'endswith', let's say, does it 'endswith("r")'.

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It does. But does it 'endswith("z")'?

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It does not.

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So it returns a Boolean.

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So that's a method. Because it's a function, is running some

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sort of logic. 'name.count'.

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Here's a good one.

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We can count the number of 'P' in here.

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And remember when we were talking about sequences and strings,

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how behind the scenes Python says, "Okay, I know you have

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a sentence in here with Zephyr", and it's going to log all

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of those individually, sort of behind the scenes.

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It's exactly what it's doing here.

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So it says 'name', run the method, the function on this 'name'

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called 'count'.

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Look for the number of 'p'.

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And so when I hit 'Enter' on this, or 'Shift + Enter' in Jupyter

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Notebook, this is going to say 1, just like that.

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Now, if you ever want to test any of these out, by all means,

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open up this notebook, hit or type, 'name.', hit tab,

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snd then you can just explore any of these that you want.

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Some of these are not going to be as intuitive as others.

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And a lot of these we're going to cover sort of throughout

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the rest of this course.

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A good one here would be 'lower'.

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Okay, it's a lot like 'upper', but just turns everything lower.

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So that 'Z' is going to be a lower case 'z', little "zephyr".

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So you can go ahead and test some of those out.

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If you ever get stuck on one of them, you can always just

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throw it into Google as well.

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You can be like, Oh, Python 'count', method, Python 'find'

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method, Python 'isascii' method, and it'll bring you to the

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Python Docs, or a StackOverflow question, or a nice blog

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post that will sort of help you understand.

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There's a lot in here, we can't possibly go through every

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single one, but there's quite a few in here that you're going to

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end up using quite often.

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So ones thought I tend to use as a web developer,

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'count', 'endswith', 'find', 'format', 'join', 'lower', 'replace' or 'rsplit'

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regular 'split', 'startswith', strip.

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'rstrip', was in there too, right? Yup.

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'rstrip', 'title' and 'upper'.

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Those are the ones I usually use on a string

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anyways. Just for funsies

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let's see what 'swapcase' does.

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Well, look at that.

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It swapped the cases.

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So that's kind of something fun that we can do.

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Now, the big thing here, the big takeaway is really the difference

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between functions and methods.

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And just as a quick little recap, a function looks like

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the function name, then it has parentheses,

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and then you put some sort of parameter inside of it, like

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'type' or 'print'. And a method looks like '.',

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and then the function name or the method name, and then parentheses,

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and it can take a parameter, might not take a parameter.

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And a property is really just a variable inside of an object

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like name.

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A good example of that is 'len(name)'.

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And Python said there were six characters in there. So somewhere

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inside of Python it says, "Hey 'name' has an attribute, that is an

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attribute, has a property, has an internal variable called

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length, and that value is 6.