1 00:00:02,530 --> 00:00:03,850 Hey everybody. 2 00:00:04,150 --> 00:00:08,240 Welcome back to Kwan's Mark pricer slopes dot com. 3 00:00:08,240 --> 00:00:13,140 And today we are going to talk about strings in the swift Threet. 4 00:00:13,690 --> 00:00:20,980 So let's go ahead and open up our X code 8 and we can actually go to file new playground. 5 00:00:20,980 --> 00:00:21,900 That's what I'm doing here. 6 00:00:21,920 --> 00:00:35,470 File new playground and let's call this string out strung out because it sounds cool. 7 00:00:36,040 --> 00:00:39,680 And let's go ahead and just save this wherever you like. 8 00:00:43,680 --> 00:00:53,550 So what is a string so we're here in the playground and a string is a core fundamental feature or type 9 00:00:54,210 --> 00:01:00,480 of data that you can use in an application and you've witnessed them many times did you ever use any 10 00:01:00,480 --> 00:01:10,000 type of app and to show you we can go ahead and open up iTunes and we can change to the apps 11 00:01:12,690 --> 00:01:16,090 actually want to go to the store here AppStore. 12 00:01:16,610 --> 00:01:17,520 OK. 13 00:01:18,060 --> 00:01:21,830 And here's a bunch of apps right. 14 00:01:21,840 --> 00:01:23,340 Just click on a random map. 15 00:01:23,610 --> 00:01:23,840 OK. 16 00:01:23,850 --> 00:01:25,160 You see these captions here. 17 00:01:25,200 --> 00:01:27,330 Happy rocket ship T-Rex. 18 00:01:27,360 --> 00:01:28,650 These are all strings. 19 00:01:28,650 --> 00:01:33,120 At some point there is textual data that is being displayed to the user and that is a string and never 20 00:01:33,150 --> 00:01:34,320 used them in every type of that. 21 00:01:34,380 --> 00:01:37,880 So that's what's going on underneath the hood. 22 00:01:38,040 --> 00:01:42,260 And even right here in the playground the first thing to start you off with is a string. 23 00:01:42,270 --> 00:01:45,750 It's a variable named s tr of type string. 24 00:01:45,750 --> 00:01:47,260 And how do you know it's a pipe string. 25 00:01:47,430 --> 00:01:54,720 Well this is called Type inference where your variable is inferring what type you're you're it's going 26 00:01:54,720 --> 00:01:55,840 to be by what you put in it. 27 00:01:55,950 --> 00:02:01,290 Meaning it's a string I can't say as TR equals 50. 28 00:02:01,340 --> 00:02:06,320 It's going to yell at me if I try and do that because as TR is the string can assign value of type it 29 00:02:06,630 --> 00:02:18,480 to type string so could also be written as string that's explicitly declared type ok whereas before 30 00:02:18,480 --> 00:02:23,310 it was inferred so that's a string and a string is a series of characters and you encompass the characters 31 00:02:23,400 --> 00:02:25,100 in double quotation. 32 00:02:25,440 --> 00:02:26,330 OK. 33 00:02:26,940 --> 00:02:29,190 And you can put any type of characters you want in there. 34 00:02:29,220 --> 00:02:33,890 Even Unicode characters emojis and things like that which is pretty cool. 35 00:02:34,080 --> 00:02:37,140 But you wouldn't put images in a string in your code. 36 00:02:37,140 --> 00:02:38,490 It's absolutely pointless. 37 00:02:38,490 --> 00:02:39,340 Don't do that. 38 00:02:39,680 --> 00:02:40,330 OK. 39 00:02:41,070 --> 00:02:42,720 So what can you do with strings. 40 00:02:42,720 --> 00:02:49,500 Well again just think of anything in a program that has strings you can do anything they've ever seen 41 00:02:49,500 --> 00:02:50,240 in the program. 42 00:02:50,400 --> 00:02:54,450 So if you've seen something in a program that has words in it that's what you can use strings with. 43 00:02:54,450 --> 00:02:56,400 So the options are very open. 44 00:02:56,580 --> 00:02:58,940 So let's just do let's just play around just to show you. 45 00:02:59,180 --> 00:03:03,270 So I'm going to create a new variable called first name like you might have this in an address book 46 00:03:03,270 --> 00:03:04,460 or anything else. 47 00:03:04,680 --> 00:03:09,430 So we'll say jack bar last name equals Bauer. 48 00:03:09,650 --> 00:03:10,040 OK. 49 00:03:10,200 --> 00:03:12,410 Jack Bauer he's a cool guy. 50 00:03:12,450 --> 00:03:13,740 Random errors and prompts. 51 00:03:13,740 --> 00:03:17,310 Currently on the X code beta years may not have these errors and problems. 52 00:03:17,490 --> 00:03:20,200 If you're using the live version which is great. 53 00:03:20,250 --> 00:03:26,130 So first name last name and then say var full name. 54 00:03:26,190 --> 00:03:27,950 So now you've got a first name and last name right. 55 00:03:27,960 --> 00:03:33,740 Jack Bauer and we've assigned it with the equals operator or the assignment operator into this variable 56 00:03:33,750 --> 00:03:37,130 so first name is equal to Jack last name is equal to about right. 57 00:03:37,140 --> 00:03:38,460 So how can we create a full name. 58 00:03:38,460 --> 00:03:41,560 Well we could just create another string right saying Jack Bauer. 59 00:03:41,560 --> 00:03:44,450 But now we're copying and pasting code we never want to do that. 60 00:03:44,640 --> 00:03:48,910 So we can actually do what is called string concatenation. 61 00:03:48,960 --> 00:03:55,420 OK we can say first name we can use the addition symbol the plus symbol here plus an empty string. 62 00:03:55,440 --> 00:03:59,740 Actually it's not an empty string plus a space plus the last name. 63 00:04:00,330 --> 00:04:06,270 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 64 00:04:06,270 --> 00:04:09,720 the first name here added and a space here. 65 00:04:09,760 --> 00:04:13,890 OK this is actually a character space and we added the last name. 66 00:04:13,890 --> 00:04:19,050 And notice how we didn't use the words themselves we use the variables because a variable is a representation 67 00:04:19,050 --> 00:04:19,490 of data. 68 00:04:19,500 --> 00:04:27,580 It has a memory location in your program on the hardware and it represents value a value of some kind. 69 00:04:27,690 --> 00:04:28,330 OK. 70 00:04:28,600 --> 00:04:30,730 And so we've just created a for name Jack Bauer. 71 00:04:30,730 --> 00:04:33,090 Now this variable has the string in it. 72 00:04:33,090 --> 00:04:35,040 Very cool very very cool. 73 00:04:35,040 --> 00:04:40,920 So in an application like an address book the data might be stored like this but when you actually open 74 00:04:40,920 --> 00:04:46,620 up your address book on iPhone and it says Jack Bauer or the full name it's actually probably Grabow 75 00:04:46,620 --> 00:04:52,110 and these two data types are there's two variables here and it's concatenated in them or in some way. 76 00:04:52,140 --> 00:04:55,090 And then it's displaying it to the user which is pretty cool. 77 00:04:55,350 --> 00:04:55,850 Really cool. 78 00:04:55,870 --> 00:05:00,990 And this is called also called string manipulation or manipulating strings here to do something else 79 00:05:00,990 --> 00:05:05,690 which is where you're going to do all the time as a developer. 80 00:05:05,690 --> 00:05:11,980 So there's our full name and we can do it another way to say full name two equals. 81 00:05:12,320 --> 00:05:13,900 Well put some quotes there. 82 00:05:13,910 --> 00:05:17,990 This is an empty string at this point and you see if you see two quotes like this this is an empty string. 83 00:05:17,990 --> 00:05:20,120 There's no characters inside of it. 84 00:05:20,170 --> 00:05:27,030 We're going to do a backslash parentheses and then another backslash in parentheses. 85 00:05:27,830 --> 00:05:32,930 And what we're going to do is we're going to put the first name in here and the last name. 86 00:05:32,990 --> 00:05:39,800 This is called string Interpol action and what it means is that you can pass variables right into your 87 00:05:39,800 --> 00:05:46,370 string so the backslash says Hey less parentheses say hey whatever comes in between these parentheses 88 00:05:46,370 --> 00:05:47,230 here. 89 00:05:47,240 --> 00:05:50,780 We're actually going to insert a variable of some kind. 90 00:05:50,780 --> 00:05:54,800 So we're going to insert the first name into here and the last name into here and here is the empty 91 00:05:54,800 --> 00:05:55,360 space. 92 00:05:55,370 --> 00:05:57,130 It gives us the exact same result. 93 00:05:57,620 --> 00:06:02,570 And you know we could play around with it we could we could also let's say we had a number here bar 94 00:06:03,140 --> 00:06:08,400 and let's say age equals 45. 95 00:06:08,600 --> 00:06:11,970 You know we could say Jack Bauer is. 96 00:06:12,050 --> 00:06:18,350 And then another one another insertion here and we put it past the edge and there you have it Jack Bauer 97 00:06:18,620 --> 00:06:20,400 is age 45. 98 00:06:20,720 --> 00:06:21,250 OK. 99 00:06:21,620 --> 00:06:22,040 Pretty good. 100 00:06:22,040 --> 00:06:28,160 So you can insert numbers you can enter numbers in here you can insert variables into a variable that's 101 00:06:28,190 --> 00:06:32,430 a value type strings as well floats doubles things like that. 102 00:06:33,080 --> 00:06:35,860 So funding's you can do with strings you can concatenate them. 103 00:06:35,900 --> 00:06:39,520 You can insert variables into them using string Interpol. 104 00:06:39,560 --> 00:06:40,210 That's the keyword. 105 00:06:40,220 --> 00:06:47,030 Write that down and string also string is a class and it has other things available to it. 106 00:06:47,030 --> 00:06:52,190 So another way to add things to it is we could say full name dot append. 107 00:06:53,180 --> 00:06:57,680 Will pass in another string and then we'll say the third. 108 00:06:57,680 --> 00:06:59,310 And so now Jack Bauer the third. 109 00:06:59,450 --> 00:06:59,740 OK. 110 00:06:59,750 --> 00:07:04,280 So you can call this nifty little append function to append something to the end of it. 111 00:07:04,340 --> 00:07:06,910 You have a lot of things available to you with a string. 112 00:07:06,920 --> 00:07:10,720 And again this fall name right here is a variable of type string. 113 00:07:10,720 --> 00:07:16,760 And when you use the dot syntax you can call different functions or properties on that's on that string 114 00:07:16,760 --> 00:07:17,480 itself. 115 00:07:17,850 --> 00:07:21,980 OK which gives you a lot of opportunities to manipulate the strings and do other things. 116 00:07:21,980 --> 00:07:26,930 In fact if you just type in full name and the DOT is there all the things that are available to you 117 00:07:27,050 --> 00:07:29,790 that you can do with your string which is which is pretty cool. 118 00:07:29,810 --> 00:07:33,610 I'm not going to go over all of them and I don't use all of them every single day. 119 00:07:33,650 --> 00:07:37,800 I use a few things a lot and a lot of the things occasionally. 120 00:07:37,820 --> 00:07:42,770 So you can append things but there's more functionality available as well too. 121 00:07:42,920 --> 00:07:44,030 You can. 122 00:07:44,180 --> 00:07:45,470 Well here's a cool one. 123 00:07:45,600 --> 00:07:48,810 Save a book title right in your app. 124 00:07:48,980 --> 00:07:53,540 Let's say it's an app where a user can store the favorite book titles and they decided not to capitalize 125 00:07:53,540 --> 00:07:54,560 anything. 126 00:07:55,190 --> 00:07:56,180 And so just look silly. 127 00:07:56,180 --> 00:08:01,480 So you know their favorite book is revenge of the crab cakes. 128 00:08:01,610 --> 00:08:02,200 OK. 129 00:08:02,510 --> 00:08:03,940 And yeah it's kind of sloppy. 130 00:08:03,950 --> 00:08:04,820 All lowercase. 131 00:08:04,850 --> 00:08:05,500 Doesn't look good. 132 00:08:05,630 --> 00:08:14,470 So what we can do is we can say book title equals and then book title capitalized. 133 00:08:14,570 --> 00:08:18,920 So what's going to happen here is it's going to call this first before it does this. 134 00:08:18,920 --> 00:08:23,960 It's going to grab your book title which is currently this and then we're going to call the capitalized 135 00:08:23,960 --> 00:08:27,710 property on it which is going to return a version of this string. 136 00:08:27,740 --> 00:08:33,350 It's going to return a copy of this except we're the first letter of each word is capitalized and then 137 00:08:33,350 --> 00:08:35,180 it's going to shove it back in the book title. 138 00:08:35,180 --> 00:08:40,720 So book title at this point when it gets here will no longer have a lower case string in it. 139 00:08:40,880 --> 00:08:41,950 OK it will look like this. 140 00:08:41,990 --> 00:08:45,770 So this is another way you might you might have seen this in a program where you put in text and then 141 00:08:46,010 --> 00:08:49,420 the program automatically capitalizes things through to make it look nice. 142 00:08:49,480 --> 00:08:54,520 It's another thing that you have available to you with strings. 143 00:08:54,600 --> 00:09:01,790 What else I have ever been in a chat room where you know everyone's cool and chill just typing nicely 144 00:09:01,790 --> 00:09:10,160 and then some punk kids like you know typing in all caps and annoying everybody you know like our chat 145 00:09:10,160 --> 00:09:13,610 room annoying caps guy. 146 00:09:13,690 --> 00:09:14,590 OK. 147 00:09:14,750 --> 00:09:20,220 And he's like ha ha that is so funny or even worse. 148 00:09:20,240 --> 00:09:24,030 He's like please help me. 149 00:09:24,060 --> 00:09:30,680 Don't do this if you're learning how to code don't go into a chat room and say please help me. 150 00:09:30,680 --> 00:09:37,190 Now here is my 100 lines of code. 151 00:09:37,340 --> 00:09:41,210 Don't do this if you've done this before. 152 00:09:41,210 --> 00:09:42,800 Know who you are. 153 00:09:42,810 --> 00:09:47,030 No one no one can talk to it in all caps especially holy smokes. 154 00:09:47,260 --> 00:09:48,820 That's not the way to get people help. 155 00:09:48,950 --> 00:09:51,920 But anyway so yeah annoying chat room guy please help me now. 156 00:09:51,940 --> 00:09:52,940 Here's one hundred lines of code. 157 00:09:52,940 --> 00:09:59,450 Well let's fix that problem so in our app in our chat app we don't want to allow this. 158 00:09:59,450 --> 00:10:03,320 We don't ever want to allow caps so we're going to just force the user never to type in caps what we're 159 00:10:03,320 --> 00:10:14,530 going to do save var lower cased chat equals chat room annoying caps guy thought lower cased and it's 160 00:10:14,540 --> 00:10:20,080 annoying caps guy because the females the women they never do it's always cool and chill and nice. 161 00:10:20,120 --> 00:10:25,350 So the guys are like me now and are now ok. 162 00:10:25,610 --> 00:10:27,700 Be nice be nice. 163 00:10:27,760 --> 00:10:30,710 Lowercase chat chat room annoying caps lowercase and now look at it. 164 00:10:30,860 --> 00:10:35,180 It's all lower case in your chat now prevent this from happening so this is a real functionality you 165 00:10:35,180 --> 00:10:38,720 might see in the real world which is kind of cool. 166 00:10:38,900 --> 00:10:41,730 You know these are just different features of the strings that I'm showing you. 167 00:10:41,750 --> 00:10:43,680 You may not even use these all the time. 168 00:10:43,700 --> 00:10:46,600 The ones that use the most are the ones right here. 169 00:10:46,780 --> 00:10:48,130 That's what ease the most. 170 00:10:48,470 --> 00:10:52,910 When you're working with strings what else. 171 00:10:53,240 --> 00:10:59,690 Like what if you like had an app for instance that kids kids could have and you don't want swear words 172 00:10:59,690 --> 00:11:00,340 or something in it. 173 00:11:00,360 --> 00:11:01,850 You know how could you get rid of those things. 174 00:11:01,850 --> 00:11:08,120 Well I'm not going to type swear words into into this program for a million people to see. 175 00:11:08,360 --> 00:11:13,310 But you know I don't know if you guys know this but if you've been around Mormons before they have their 176 00:11:13,310 --> 00:11:15,650 own vocabulary of swear words OK. 177 00:11:15,710 --> 00:11:23,990 Like you know heck you know they say what do they say Oh heck you know fetch. 178 00:11:24,870 --> 00:11:29,500 You know she is. 179 00:11:31,100 --> 00:11:32,870 But anyway those are some common ones right. 180 00:11:32,870 --> 00:11:33,960 Heck and fetch. 181 00:11:33,980 --> 00:11:34,540 OK. 182 00:11:34,750 --> 00:11:39,960 So listen we want an app that gets you know that stops where we're Subha Mormons where it works OK. 183 00:11:39,980 --> 00:11:43,490 So what we're going to do and I can I can bring this up because I'm a Mormon. 184 00:11:43,490 --> 00:11:47,160 I can say whatever I want so don't think I'm out there offending people. 185 00:11:47,210 --> 00:11:54,140 So I say in this chat up again we want to take out cusswords or in this case the Mormon cusswords you 186 00:11:54,140 --> 00:12:01,220 know we're going to say what the French and heck that is crazy like you know we don't want we don't 187 00:12:01,220 --> 00:12:06,290 want this in our chat room so we can do a little bit of logic which we haven't really covered yet. 188 00:12:06,300 --> 00:12:16,430 But using an if statement and I can say if sentence contains and we can say so if the sentence contains 189 00:12:16,430 --> 00:12:27,080 this word or the double pipes and the symbol under the backspace key or sentence that contains Pech. 190 00:12:27,110 --> 00:12:32,530 All right so if this sentence contains fetch or heck then what can we do. 191 00:12:32,660 --> 00:12:37,900 Well we can say sentence that replacing occurrences of. 192 00:12:37,900 --> 00:12:48,770 So let's replace all occurrences of fetch with tuna and sentence replacing all occurrences of him will 193 00:12:48,770 --> 00:12:53,930 replace heck with player. 194 00:12:54,080 --> 00:12:58,970 Just for fun and like that what the tuna heck. 195 00:12:59,030 --> 00:12:59,600 That is crazy. 196 00:12:59,600 --> 00:13:04,340 And then in this in this case here you know what the player that is crazy. 197 00:13:04,520 --> 00:13:05,810 So pretty cool. 198 00:13:06,110 --> 00:13:08,090 You can do fun little things like that you can. 199 00:13:08,420 --> 00:13:12,660 You can find occurrences of strange you can remove them. 200 00:13:13,160 --> 00:13:19,880 We covered really like ninety nine point nine percent of what you'll be using strings for over and over 201 00:13:19,880 --> 00:13:24,680 and over and over again which is which is pretty awesome you don't have to know that much in order to 202 00:13:24,680 --> 00:13:27,140 be fully functional and up and running. 203 00:13:27,470 --> 00:13:33,640 So just to repeat some of the key words here and also to recap on variables when you have the colon 204 00:13:33,670 --> 00:13:35,400 and the type here this is. 205 00:13:35,450 --> 00:13:40,490 This means you're explicitly declaring a type or the key word is explicitly declared type if you want 206 00:13:40,490 --> 00:13:41,590 to write that down. 207 00:13:41,660 --> 00:13:48,350 If you take off the colon and the type this is called Type inference the variable is inferring that 208 00:13:48,350 --> 00:13:52,430 this is of type string because that's the data that we're passing into it and by the way this is the 209 00:13:52,430 --> 00:13:58,850 recommended way and swift is to use type inference whenever you can and not explicit types can. 210 00:13:59,330 --> 00:14:03,070 You can do string concatenation using the plus symbol. 211 00:14:03,080 --> 00:14:08,930 Adding strings together you can use string interpolation where you can insert variables in the strings 212 00:14:09,080 --> 00:14:11,030 like so using the backslash. 213 00:14:11,030 --> 00:14:16,620 And then the parentheses in the variable and sign you can add things to a string using append. 214 00:14:16,700 --> 00:14:21,890 You can do some cool things like capitalize the first letter in each word using the capitalized property 215 00:14:22,130 --> 00:14:23,870 capitalized. 216 00:14:23,900 --> 00:14:28,860 You can get lowercase the lower case versions of a word. 217 00:14:28,970 --> 00:14:34,010 And if you were wondering why does this lowercase here have parentheses but capitalized is not that 218 00:14:34,010 --> 00:14:37,150 is it because capitalized is a property. 219 00:14:37,150 --> 00:14:38,180 It's a variable. 220 00:14:38,180 --> 00:14:38,840 OK. 221 00:14:38,960 --> 00:14:41,290 Whereas lowercase is actually a function. 222 00:14:41,300 --> 00:14:49,010 So if I command click this it's not working so dominating the show but this is a property meaning it's 223 00:14:49,010 --> 00:14:53,960 a variable in the string class whereas this is a function in the string class the block should do something 224 00:14:53,960 --> 00:14:55,520 and return a value. 225 00:14:55,700 --> 00:14:56,560 There is a difference. 226 00:14:56,570 --> 00:14:57,890 You'll learn as you go along. 227 00:14:57,980 --> 00:15:03,530 So you get the lowercase version you can get rid of cusswords in an app or whatever you want or just 228 00:15:03,620 --> 00:15:07,080 even find strings by using the contained keyword and passing in the word. 229 00:15:07,190 --> 00:15:10,000 And then you can do things with it like replace. 230 00:15:10,170 --> 00:15:11,030 Really cool stuff. 231 00:15:11,030 --> 00:15:12,600 So this is strings. 232 00:15:12,610 --> 00:15:14,910 You use them all the I'm not much more to say about it. 233 00:15:14,920 --> 00:15:17,860 Mark Price at slopes dot com. 234 00:15:17,930 --> 00:15:18,550 You next.