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Hey everybody.

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Welcome back to quote Mark pricer slopes dot com.

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And today we are going to talk about strings in the swift Threet.

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So let's go ahead and open up our X code 8 and we can actually go to file new playground.

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That's what I'm doing here.

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File a new playground and let's call this string out strung out because it sounds cool.

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And let's go ahead and just save this wherever you like.

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OK.

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So what is a string.

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So we're here in the playground and a string is a core fundamental feature or type of data that you

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can use in an application.

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And you've witnessed them many times.

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If you've ever used any type of app and to show you we can go ahead and open up iTunes and we can change

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to the apps.

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I actually want to go to the store here.

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App Store.

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OK.

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And here's a bunch of apps right.

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Just click on a random map.

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OK.

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You see these captions here.

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Happy rocketship T-Rex.

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These are all strings.

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At some point there is textual data that is being displayed to the user and that is a string and never

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used them in every type of that.

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So that's what's going on underneath the hood.

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And even right here in the playground the first thing you start off with is the string.

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It's a variable named s tr of type string.

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And how do you know it's a pipe string.

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Well this is called Type inference where your variable is inferring what type you're you're it's going

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to be by what you put in it meaning it's a string.

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I can't say as Tiahrt equals 50.

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It's going to yell at me if I try and do that because as TR is the string can assign value of type int

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to type String OK so could also be written as string that's explicitly declared type K whereas before

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it was inferred.

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So that's a string and a string is a series of characters and you encompass the characters in double

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quotation.

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OK.

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And you can bet any type of characters you want in there.

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Even Unicode characters emojis and things like that which is pretty cool.

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But you wouldn't put images in a string in your code.

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It's absolutely pointless.

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Don't do that.

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OK.

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So what can you do with strings.

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Well again just think of anything in a program that has strings you can do anything they've ever seen

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in a program.

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So if you've seen something in a program that has words in it that's what you can use strings with.

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So the options are very open.

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So let's just do let's just play around just to show you.

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So I'm going to create a new variable called first name like you might have this in an address book

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or anything else.

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So we'll say jack bar last name equals Bauer.

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OK.

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Jack Bauer he's a cool guy.

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Random errors and prompts.

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Currently on the X code beta you may not have these errors and problems.

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If you're using the live version which is great.

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So first name last name and square and say var full name.

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So now you've got a first name and last name right.

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Jack Bauer.

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And we've assigned it with the equals operator or the assignment operator into this variable so first

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name is equal to Jack last name is equal to about right.

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So how can we create a full name.

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Well we could just create another string right saying Jack Bauer.

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Now we're copying and pasting code we never want to do that.

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So we can actually do what is called string concatenation.

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Because because first name and we can use the addition symbol the plus symbol here plus an empty string.

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Actually it's not an empty string plus a space.

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Plus the last name.

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So if you look over here in the right hand side it now says Jack Bauer So all we've done is we've taken

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the first name here added and a space here.

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OK this is actually a character space and we added the last name.

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And notice how we didn't use the words themselves we use the variables because a variable is a representation

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of data.

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It has a memory location in your program on the hardware and it represents value a value of some kind.

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OK.

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And so we've just created a file name Jack Bauer.

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Now this variable has the string in it.

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Very cool very very cool.

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So in an application like an address book the data might be stored like this but when you actually open

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up your address book on iPhone and it says Jack Bauer or the full name it's actually probably grabbing

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these two data types.

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Are these two variables here.

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And it's concatenated in them or in some way and then it's displaying it to the user which is pretty

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cool.

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Really cool.

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And this is called also called string manipulation or manipulating strings here to do something else

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which is what you're going to do all the time as a developer so there's our full name and we can do

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it another way to say full name to equals.

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Well put some quotes there.

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This is an empty string at this point and if you see two quotes like this this is an empty string there's

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no characters inside of it.

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We're going to do a backslash parentheses.

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And then another backslash in parentheses.

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And what we're going to do is we're going to put the first name in here.

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And the last name.

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This is called string Interpol action and what it means is that you can pass variables right into your

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string so the backslash says hey backslash parentheses say hey whatever comes in between these parentheses

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here.

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We're actually going to insert a variable of some kind.

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So we're going to insert the first name into here and the last name into here and here is the empty

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space.

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It gives us the exact same result.

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And you know we could play around with it we could we could also let's say we had a number here bar

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and let's say age equals 45.

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You know we could say Jack Bauer is.

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And then another one another insertion here and we put it past the edge and there you have it Jack Bauer

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is age 45.

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OK.

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Pretty good.

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So you can insert numbers.

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You can enter numbers in here you can insert variables and type a variable that's a value type strings

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as well floats doubles things like that.

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So funding's you can do with strings you can concatenate them you can insert variables into them using

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string Interpol.

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That's the keyword.

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Write that down and string also string is a class and it has other things available to it.

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So another way to add things to it is we could say full name dot append will pass in another string

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and then we'll say the third.

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And so now Jack Bauer the third.

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OK.

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So you can call this nifty little append function to append something to the end of it.

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You have a lot of things available to you with a string.

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And again this fall name right here is a variable of type string.

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And when you use the dot syntax you can call different functions or properties on that's on that string

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itself.

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OK which gives you a lot of opportunities to manipulate strings and do other things.

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In fact if you just type in full name and the DOT is there all the things that are available to you

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that you can do with your string which is which is pretty cool.

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And I'm going to go over all of them and I don't use all of them every single day.

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I use a few things a lot and a lot of the things occasionally.

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So you can append things but there's more functionality available as well too.

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You can.

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Well here's a cool one.

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Save a book title right in your app.

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Let's say it's an app where a user can store the favorite book titles and they decided not to capitalize

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anything.

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And so just look silly.

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So you know their favorite book is revenge of the crab cakes.

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OK.

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And yeah it's kind of sloppy.

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All lowercase.

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Doesn't look good.

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So what we can do is we can say book title equals and then book title capitalized.

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So what's going to happen here is it's going to call this first before it does this.

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It's going to grab your book title which is currently this and then we're going to call the capitalized

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property on it which is going to return a version of this string.

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It's going to return a copy of this except we're the first letter of each word is capitalized and then

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it's going to shove it back in the book title.

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So book title at this point when it gets here will no longer have a lower case string in it.

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OK it will look like this.

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So this is another way you might you might have seen this in a program where you put in text and then

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the program automatically capitalizes things through to make it look nice.

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It's another thing that you have available to you with strings.

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What else I have ever been in a chat room where you know everyone cool and chill just typing nicely

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and then some punk kids like you know typing in all caps and annoying everybody you know like our chat

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room annoying caps guy.

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OK.

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And he's like Ha.

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That is so funny.

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Or even worse.

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He's like please help me.

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Don't do this.

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If you're if you're learning how to code don't go into a chat room and say please help me.

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Now here is my 100 lines of code.

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Don't do this if you've done this before.

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Know who you are.

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No one no one want to turn on caps is specially Holy smokes.

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That's not the way to get people help.

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But anyway so yeah annoying chat room guy please help me now.

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Here's one hundred lines of code.

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Well let's fix that problem so in our app in our chat app we don't want to allow this.

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We don't ever want to allow caps so we're going to just force the user never to type in caps so what

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we're going to do save our lower case chat equals chat room annoying caps guy thought lower case and

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it's annoying caps guy because the females the women they never do it's always cool and chill and nice.

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So the guys are like me now and are now ok.

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Be nice be nice.

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Lowercase chat chat room annoying caps lowercase and now look at it.

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It's all lower case that your chat now prevents this from happening so this is a real functionality

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you might see in the real world which is kind of cool.

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You know these are just different features of the strings that I'm showing you.

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You may not even use these all the time.

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The ones that you use the most are the ones right here.

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That's what is the most when you're working with strings.

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What else.

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Like what if you like had an app for instance that kids kids could have and you don't want swear words

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or something in it.

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You know how could you get rid of those things.

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Well I'm not going to type swear words into into this program for a million people to see.

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But you know I don't know if you guys know this but if you've been around Mormons before they have their

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own vocabulary of swear words OK.

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Like you know heck they say what do they say.

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Oh heck you know that.

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You know she is.

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But anyway those are some common ones right.

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Heck and fetch.

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OK so let's say we want an app that gets you know that stops where we're Subha Mormons where it works

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OK.

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So what we're going to do and I can I can bring this up because I'm a Mormon.

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I can say whatever I want so don't think I'm out there offending people.

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So I say in this chat up again we want to take out cusswords or in this case the Mormon cusswords you

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know we're going to say what the French and heck that is crazy like you know we don't want we don't

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want this in our chat room so we can do a little bit of logic which we haven't really covered yet.

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But using an if statement and I can say if sentence contains and we can say so if the sentence contains

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this word or the double pipes and the symbol under the backspace key or sentence that contains Pech.

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All right so if this sentence contains fetch or heck then what can we do.

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Well we can say sentence that replacing occurrences of.

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So let's replace all occurrences of fetch with tuna and sentence replacing all occurrences of him will

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replace heck with player.

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Just for fun and like that what the tuna heck.

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That is crazy.

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And then in this in this case here you know what that player that is crazy.

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So pretty cool.

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You can do fun little things like that you can you can find occurrence of strange you can remove them.

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We covered really like ninety nine point nine percent of what you'll be using strings for over and over

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and over and over again which is which is pretty awesome you don't have to know that much in order to

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be fully functional and up and running.

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So just to repeat some of the key words here and also to recap on variables when you have the colon

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and the type here this is.

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This means you're explicitly declaring a type or the key word is explicitly declared type if you want

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to write that down.

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If you take off the colon and the type this is called type inference the variable is inferring that

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this is of type string because that's the data that we're passing into it and by the way this is the

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recommended way and swift is to use type inference whenever you can and not explicit types can.

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You can do string concatenation using the plus symbol.

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Adding strings together you can use string interpolation where you can insert variables into strings

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like so using the backslash.

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And then the parentheses in the variable and.

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You can add things to a string using append.

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You can do some cool things like capitalize the first letter in each word using the capitalized property.

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Capitalize.

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You can get lowercase the lower case versions of a word.

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And if you were wondering why does this lowercase here have parentheses but capitalized is not that

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is it because capitalized is a property.

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It's a variable.

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OK whereas lowercase is actually a function.

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So if I command click this it's not working.

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So dominating the show you but this is a property meaning it's a variable in the string class whereas

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this is a function in the string class that should do something and return a value.

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There is there is a difference.

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You'll learn as you go along.

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So you get the lowercase version you can get rid of cusswords in an app or whatever you want or just

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find strings by using the contains key word and passing in the word and then you can do things with

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it like replace.

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Really cool stuff.

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So this is strings.

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You use them all the time not much more to say about it.

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Mark Harris devs Lopes dot com and.