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Welcome back.

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So far, we've learned a few built in functions that Python has few built in actions, right.

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Actions that we can take on data.

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And we learned about SDR.

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We learned about it.

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We learned about float and the type conversion that we can do.

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We also learned about type.

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We also learned about print and these built-In functions in Python.

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Well, there's a few of them and I'll link to this resource, but there's not too too many.

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As a matter of fact, we've also seen ones like ABB's or round.

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In our numbers video.

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So numbers had some functions that we can use, some built in functions well, string's also has a very

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useful one called Lente, which stands for LENTH, so as you guessed it.

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If I type in something like this and I print this out.

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And I click, run, I get nine because it's calculating the length of the strength in our case one,

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two, three, four, five, six, seven, eight, nine, the length of the string is nine.

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Now, you have to be careful here because the length itself doesn't start at zero, as we've seen with

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indexes.

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Instead, it counts like humans do from one.

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So a neat thing to do here is I can do something like this.

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Let's say that we have a variable greed that equals halloo.

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Well, I can grab the Grete.

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Variable, which is a string and use string slicing to grab well, the first and then go all the way

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until the end.

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Now, the default already does this.

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If I leave it like this, it's going to grab hello and make sure I add a bracket here.

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Let's click run.

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I get hello.

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Now, if I do zero to length of.

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What does that mean?

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Well, if I click run, I still get hello because the length of Grete.

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Is nine.

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Like, so now this lenth function is quite useful and we're going to use it a lot in this course, but

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I want to introduce to you the concept of built in functions.

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As well as what we call builtin methods, hmm, what does that mean?

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A built in function had the syntax of the word that was highlighted in blue, and then we used curly

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brackets to perform some action on a data type.

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However, Python also has this idea of methods and methods are similar to functions, but they they

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are owned by something.

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So, for example, in Python, we have string methods.

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So these are methods or actions that only strings can perform.

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And don't worry.

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This is something that we'll talk more about when we talk about classes and functions.

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But for now, Python, for example, has a string methods.

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So these are methods that we can use specifically for strings and methods, have a special syntax where

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instead of just the word with the curly brackets, it usually has a dot in front of it.

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So dot and then some sort of word.

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And we've actually seen one format, right?

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DOT format, curly brackets or brackets is a method.

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And if I go to Python string methods and I scroll down or scroll up, we see that format, format,

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specific values and a string is a method.

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Now, why do we care?

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Well.

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With this, python gives us automatic tools that we can use on strength, so let's explore some of these

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string methods.

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Let's create a quote here, and the quote is going to be to be or not to be.

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Now, in here with this quote, We can use some methods on this string now I'm not going to go through

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everything because, well, 60 percent of these you're most likely never going to use in your career.

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I'm going to go over the important ones that you'll see over and over again.

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But I'll also link to this so that you can see this for yourself as a reference.

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Remember, as a programmer, your job is not to memorize this and read a language like you read a dictionary

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instead is to know that this resource exists and it's for you to explore and learn as a specific problem

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occurs.

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But let's get back to the task at hand.

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One thing that we can do is to use the upper method, we use a dot and then type in upper and then the

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curly brackets.

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And luckily for us, our Ed shows us that this actually exists because of the drop down menu.

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So what happens now if I print this?

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Look at that, everything gets capitalized to be or not to be.

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There is also another one we can use called Capitalize.

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What's the difference between the two?

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Well, if I run, you see that it capitalizes the beginning of the sentence.

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And by the way, your editor or in our case, our Reppel, if you hover over this, will actually tell

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you what it does.

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It returns a capitalized version of S..

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So whatever is to the left of the.

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And a good editor will actually show you all the things available to you, so as soon as you press a

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dot, look at that, I see all these purple boxes, which are methods that are available to me for a

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string.

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And you see there's a lot of them.

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Now, don't worry about these double underscores these Dundar methods, because this is something that

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we'll talk about when we talk about classes.

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But you can see that you have different things that you can use.

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For example, you have lower instead of upper and lower cases, everything.

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What if I want to use find, for example?

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And Fine simply says, hey, does B exist in the code to be or not to be, in fact, like run?

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Well, it tells me that, yes, I could not find has a B and it starts at index of three.

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So if I go to zero one, two and then look at that three, so we have to find which finds us the first

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occurrence of a piece of text.

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You also have things like replace where I can replace whatever I give it as the first thing and then

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separate it to the second thing.

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So you can see over here, it tells me old and then comma new and I can replace this with me if I click

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run.

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I get to me or not to me, so this replaces all the occurrences of the now the final thing I want to

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point out to you is that if I print here, quote, what do you think is going to happen?

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I've printed here and I replaced to me to be or not to be with.

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To me or not to me.

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Quite a selfish quote, but if I print this again on the fifth line, what do you think will happen?

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Let's find out.

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Is this what you expected?

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Think about why this might happen based on what we've learned.

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Here's the thing, remember, strings are immutable, that is they cannot be changed.

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We can overwrite them if we want, but we don't change them.

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We either create them or destroy them.

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In our case, when we do, quote, replace to me or not to me, it's creating a new string.

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Now, we're not assigning the string to anything, so eventually after we printed, we remove it from

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memory.

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But if I do something like.

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This where I have.

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Quote, two equals, quote, I replace and I print quote to.

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Well, in our case, we're creating a whole new string, we're creating a string, but we never modify

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the original string because it's immutable.

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So that quote always stays the way it is until we destroy it.

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Until we remove it.

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Our program ends.

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This is going to exist.

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Hope you're having fun, hang in there more to learn in the next video.