Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:00,030 --> 00:00:02,310 All right guys, it's time to show what you're made of. 2 00:00:02,370 --> 00:00:05,700 Here's another code challenge. And this one is again, 3 00:00:05,790 --> 00:00:10,560 another difficult challenge and the arms really show you just how difficult it 4 00:00:10,560 --> 00:00:14,040 is, but you're going to flex and you're going to get stronger. 5 00:00:14,580 --> 00:00:17,910 And it's only through struggle that you're going to become a better coder. 6 00:00:18,480 --> 00:00:22,950 So in this code exercise, we're going to build a love calculator. 7 00:00:23,640 --> 00:00:28,640 And the way that it's going to work is the same method that I used when I was 8 00:00:29,010 --> 00:00:30,090 10, pretty much. 9 00:00:30,690 --> 00:00:35,310 And I really recommend reading up on this particular Buzzfeed article, 10 00:00:35,940 --> 00:00:38,730 which is of course, very reputable 11 00:00:38,880 --> 00:00:42,450 and it's going to tell you exactly how this program is going to work. 12 00:00:43,110 --> 00:00:47,490 So once you've managed to scroll past all the GIFs, it will tell you, um, 13 00:00:47,580 --> 00:00:51,210 the method. So you write your name, his or her name, 14 00:00:51,540 --> 00:00:54,480 and then the words true and love. Now, 15 00:00:54,480 --> 00:00:59,480 then you are going to count the number of times T-R-U-E occur in both of 16 00:00:59,520 --> 00:01:02,640 your names. And then you're going to count the number of times, 17 00:01:02,640 --> 00:01:07,560 L-O-V-E occur in both of your names. Once you've got those numbers, 18 00:01:07,590 --> 00:01:12,570 so here T-R-U-E adds up to six, L-O-V-E adds up to three. 19 00:01:12,900 --> 00:01:17,550 Then you'll get the percentage that you are compatible with this other person. 20 00:01:18,060 --> 00:01:20,550 So not only did you get to learn Programming on this course, 21 00:01:20,550 --> 00:01:22,650 you also get the discover your destiny. 22 00:01:23,190 --> 00:01:28,190 The idea is that we're going to convert this very time-consuming process into a 23 00:01:28,500 --> 00:01:32,880 computer program. So once you've understood how it works, 24 00:01:33,150 --> 00:01:35,820 you're going to write the code for it. Now, 25 00:01:35,850 --> 00:01:37,950 in order to be able to calculate the love score, 26 00:01:37,950 --> 00:01:41,340 there's two important things that you should read in the hint. 27 00:01:41,940 --> 00:01:46,940 One is you will need to use the lower function, and all that this does is it 28 00:01:48,360 --> 00:01:51,390 takes a string, let's say we've got the string Angela. 29 00:01:51,780 --> 00:01:54,990 And notice how that first letter is a capital A. 30 00:01:55,680 --> 00:01:58,770 If I write .lower parentheses, 31 00:01:59,220 --> 00:02:04,020 then it will reduce all of the capital letters to lowercase letters. 32 00:02:04,590 --> 00:02:08,220 And if you were wondering how you would've known to use this, 33 00:02:08,580 --> 00:02:11,190 then you can head over to the Stack of flow question 34 00:02:11,670 --> 00:02:15,960 in which somebody asks exactly this question, how do you turn something 35 00:02:15,960 --> 00:02:19,740 that's uppercase into a lowercase character in Python. 36 00:02:20,970 --> 00:02:23,820 The second function you'll need is the count function. 37 00:02:24,150 --> 00:02:28,350 And this will give you the number of times a letter occurs in a string, 38 00:02:28,380 --> 00:02:33,270 which is super useful when it comes to this particular challenge. So again, 39 00:02:33,300 --> 00:02:37,830 let's use our string, Angela, and then I'm going to write count. 40 00:02:38,040 --> 00:02:39,930 And then in between the parentheses, 41 00:02:40,230 --> 00:02:43,350 I'm going to specify what it is that I want to count. 42 00:02:43,740 --> 00:02:48,570 So let's say I want to count the character A inside this string, 43 00:02:48,930 --> 00:02:51,270 and I hit enter. It comes up with one, 44 00:02:51,780 --> 00:02:56,190 even though you can see there's actually two A's in the string, in my name, 45 00:02:56,760 --> 00:03:01,760 it only counts one lowercase a. So that's why this first step was super, 46 00:03:02,320 --> 00:03:03,370 super useful. 47 00:03:03,610 --> 00:03:08,320 So let's say lower_case_name equals, um, 48 00:03:09,250 --> 00:03:13,660 Angela.lower. And then, 49 00:03:13,900 --> 00:03:14,733 um, 50 00:03:14,890 --> 00:03:19,890 let's go ahead and do lower_case_name.count, 51 00:03:21,730 --> 00:03:26,440 and then we're going to count for a again. Now you'll see it gives us two, 52 00:03:26,680 --> 00:03:29,110 because we were able to convert everything to lowercase, 53 00:03:29,260 --> 00:03:33,610 and then use the count function to check the number of times the character a 54 00:03:33,670 --> 00:03:38,080 occurs in this string. And again, I've linked to a Stack Overflow question 55 00:03:38,350 --> 00:03:43,350 which is how you might've found out to use this count function and how you might 56 00:03:43,660 --> 00:03:46,900 use it in terms of code examples. Now, 57 00:03:46,930 --> 00:03:49,120 there's a second step to this challenge 58 00:03:49,120 --> 00:03:52,270 because not only do we want to know the love score, 59 00:03:52,390 --> 00:03:55,450 we also want to give the user an interpretation. 60 00:03:55,930 --> 00:04:00,930 So the interpretation is here. For love scores that are less than 10 or greater 61 00:04:02,020 --> 00:04:06,880 than 90, the message is going to say "Your score is X." And of course, 62 00:04:06,880 --> 00:04:11,770 replace that X with the actual score. You go together like Coke and Mentos. 63 00:04:13,960 --> 00:04:16,960 Now, if their love score was between 40 and 50, 64 00:04:16,990 --> 00:04:20,470 the message is going to read your score is, whatever it may be, 65 00:04:20,950 --> 00:04:24,460 you are all right together. And finally, 66 00:04:24,490 --> 00:04:28,600 for all other scores, the message is just going to give them their score. 67 00:04:28,630 --> 00:04:33,340 Your score is XYZ. In this case, there's two inputs, 68 00:04:33,370 --> 00:04:35,530 somebody's name, and then somebody else's name. 69 00:04:35,890 --> 00:04:39,670 And then you're going to check for the number of times T-R-U-E occurs in 70 00:04:39,670 --> 00:04:43,060 both of those names, L-O-V-E occurs in those names, 71 00:04:43,330 --> 00:04:46,810 then you going to combine these digits together to get a love score. 72 00:04:47,590 --> 00:04:51,670 Pause the video now, have a look at everything that's in the instructions, 73 00:04:51,910 --> 00:04:54,340 read it all and then go ahead and give that a go. 74 00:04:54,660 --> 00:04:59,660 [inaudible] 75 00:05:03,210 --> 00:05:07,950 All right. So the first step is to work out the love score, right? 76 00:05:08,160 --> 00:05:13,160 So we need to figure out how many times each of these letters occur in these 77 00:05:14,250 --> 00:05:15,083 names. 78 00:05:15,390 --> 00:05:20,390 The first thing that we need to do is to combine the names, 79 00:05:21,120 --> 00:05:23,400 because we're looking for the number of times, 80 00:05:23,400 --> 00:05:28,400 let's say a T occurs in these names and we're treating them as one string, 81 00:05:30,030 --> 00:05:33,150 right? So I don't wanna check it separately and then have to add it together. 82 00:05:33,600 --> 00:05:38,600 So let's call it a combined_string and lets set that to equal name1 + name2. 83 00:05:41,080 --> 00:05:45,150 And this is just going to concatenate those two strings together 84 00:05:45,540 --> 00:05:49,440 so we'll be able to check them only once. It makes it more efficient, 85 00:05:49,500 --> 00:05:53,760 right? The next step is to guard against cases 86 00:05:53,790 --> 00:05:57,830 where the user is inputting their name like this, which many people do, 87 00:05:58,160 --> 00:06:00,530 or they might even write it like this. 88 00:06:00,920 --> 00:06:03,980 So we have to turn everything into lowercase. 89 00:06:04,130 --> 00:06:06,080 So let's call it a lower_case_string 90 00:06:09,460 --> 00:06:14,460 and that will be combined_string. lower just as I demoed previously using 91 00:06:15,820 --> 00:06:20,050 this lower function. So now we've got everything in lower case, 92 00:06:20,080 --> 00:06:23,590 we're going to start checking for this first word, 93 00:06:23,980 --> 00:06:27,070 T-R-U-E. So let's first check 94 00:06:27,100 --> 00:06:32,100 how many times the letter T occurs in this lowercase string of both people's 95 00:06:33,070 --> 00:06:33,903 names. 96 00:06:34,030 --> 00:06:38,500 So we can say lower_case_string.count 97 00:06:38,920 --> 00:06:42,820 and then inside the parentheses, we specify the string we're looking for 98 00:06:42,850 --> 00:06:47,350 which is 't' and then I'm going to save this to a variable 99 00:06:47,350 --> 00:06:52,330 which I'll just call 't' again. And then we're going to repeat this several times, 100 00:06:52,810 --> 00:06:56,890 hopefully for practice sake, you'll type it all out. But in my case, 101 00:06:56,950 --> 00:07:01,180 I'm just going to copy and paste it, which is usually error-prone, 102 00:07:01,240 --> 00:07:03,010 but we'll try to be careful. 103 00:07:05,620 --> 00:07:08,830 So now that we've got the number of times 't' occurs, 'r' 104 00:07:08,830 --> 00:07:12,760 occurs, 'u' and 'e' occurs, we can now add it all up. 105 00:07:13,240 --> 00:07:18,240 So let's say true = t + r + u + e. 106 00:07:21,160 --> 00:07:26,160 So now we've got the first digit of our love score and we have to go ahead and 107 00:07:26,800 --> 00:07:31,690 do the same thing for L-O-V-E. So again, for time sake, 108 00:07:31,690 --> 00:07:36,690 I'm just going to copy that and then go ahead and change this to l, 109 00:07:39,100 --> 00:07:44,100 o, v, e and l, o, v, e. 110 00:07:47,050 --> 00:07:51,580 And then I'm going to go ahead and calculate the total for that 111 00:07:51,670 --> 00:07:56,670 which is going to be l + o + v + e. 112 00:07:58,690 --> 00:08:03,690 And now I've got both of these numbers and I'm going to try and concatenate them 113 00:08:04,960 --> 00:08:08,290 together to achieve this two-digit number. 114 00:08:09,340 --> 00:08:12,640 To do that, I'm going to create a love score variable 115 00:08:12,700 --> 00:08:14,170 that's going to keep hold of this. 116 00:08:14,620 --> 00:08:18,130 And then I'm going to say true + love. 117 00:08:18,760 --> 00:08:23,260 And remember that at this stage, both true and love are actually integers. 118 00:08:23,290 --> 00:08:25,510 That's how we were able to add them together. 119 00:08:26,050 --> 00:08:30,310 So if I want to turn them into a string in order to be able to concatenate them 120 00:08:30,310 --> 00:08:33,070 together, I have to convert them to strings. 121 00:08:35,200 --> 00:08:40,200 The final thing we have to do is just to go ahead and print this love score. 122 00:08:40,870 --> 00:08:43,390 So we're not going to print anything else for now. 123 00:08:43,420 --> 00:08:47,440 Let's just go ahead and test it out. So let's run our code 124 00:08:49,630 --> 00:08:52,990 and let's type my name and then 125 00:08:53,080 --> 00:08:57,750 their name, Jack Bauer, of course. And then it gives us the score. 126 00:08:57,750 --> 00:08:59,730 So five, three. 127 00:09:00,480 --> 00:09:03,780 So that means everything so far has pretty much worked. 128 00:09:04,350 --> 00:09:09,350 So now all we have to do is use our knowledge of if statements to give a 129 00:09:09,570 --> 00:09:13,050 corresponding interpretation or a message. 130 00:09:13,740 --> 00:09:17,880 If the score is less than 10 or greater than 90, 131 00:09:18,330 --> 00:09:23,330 so if love_score is less than 10 or love_score is greater than 90, 132 00:09:28,710 --> 00:09:33,710 so we're using that logical or operator here to check if either this condition 133 00:09:35,310 --> 00:09:39,660 or this condition is true. And if you find it helpful, 134 00:09:39,660 --> 00:09:41,610 which I usually do, 135 00:09:41,820 --> 00:09:46,770 it's easy to wrap these conditions in their own set of parentheses. 136 00:09:47,220 --> 00:09:51,000 Now, Python doesn't actually care. Either method works. 137 00:09:51,300 --> 00:09:54,660 But for us humans, this is a little bit more readable. 138 00:09:55,470 --> 00:09:57,630 So under this condition, 139 00:09:57,750 --> 00:10:00,510 what we're going to print out is 140 00:10:02,370 --> 00:10:04,530 Your love score is, 141 00:10:04,770 --> 00:10:07,980 and then we'll insert the love_score variable here, 142 00:10:09,450 --> 00:10:12,900 and we're going to of course be using f-strings, so let's add that. 143 00:10:13,530 --> 00:10:18,530 And then we're going to write you go together like Coke and Mentos. 144 00:10:22,350 --> 00:10:25,530 So that's our first condition done. Now, 145 00:10:25,560 --> 00:10:30,560 the next condition is what if their love score is between 40 and 50. 146 00:10:32,730 --> 00:10:35,550 So let's go ahead and add an elif here. 147 00:10:38,190 --> 00:10:38,970 Elif 148 00:10:38,970 --> 00:10:43,970 the love_score is greater than or equal to 40 149 00:10:47,220 --> 00:10:52,220 and the love_score is less than or equal to 50, 150 00:10:53,130 --> 00:10:58,130 so that catches the cases where the love score is between 40 and 50. 151 00:10:58,440 --> 00:11:03,440 So both of these conditions must be true for this statement to fire. 152 00:11:05,100 --> 00:11:06,060 And in this case, 153 00:11:06,090 --> 00:11:10,770 what we want to do is we want to print out this sentence. 154 00:11:11,670 --> 00:11:13,830 So your score is, 155 00:11:15,420 --> 00:11:18,000 let's just insert the love_score in here. 156 00:11:18,410 --> 00:11:22,790 [inaudible] 157 00:11:23,330 --> 00:11:27,530 Your score is this particular love score. You are alright together. 158 00:11:28,430 --> 00:11:33,430 Now the final thing we said is if it doesn't match any of these conditions, 159 00:11:33,860 --> 00:11:36,980 then the message is just going to be their score. 160 00:11:37,520 --> 00:11:41,900 So that means we can catch everything else using an else statement 161 00:11:42,260 --> 00:11:46,100 and we can simply just print "Your score 162 00:11:46,220 --> 00:11:48,830 is this particular number." 163 00:11:50,210 --> 00:11:54,430 Now at this stage, you might think you're done, but if you actually run it, 164 00:11:54,460 --> 00:11:59,140 you're going to get an error. So let's go ahead and test it with the same names 165 00:11:59,140 --> 00:11:59,973 as before. 166 00:12:02,440 --> 00:12:05,650 You can see that we get a type error on line 27, 167 00:12:06,040 --> 00:12:11,040 and it says that the comparison less than is not supported between instances 168 00:12:12,400 --> 00:12:13,810 of string and int. 169 00:12:14,320 --> 00:12:19,320 So the problem here is that in order to concatenate these two numbers, 170 00:12:19,960 --> 00:12:22,270 we had to turn them into strings. 171 00:12:22,750 --> 00:12:27,700 So that let's say that this number was equal to five and this number was equal 172 00:12:27,700 --> 00:12:31,900 to six. Then instead of getting 11, which is not what we want, 173 00:12:32,290 --> 00:12:37,290 we actually get 56 'cause they're both strings and these strings get concatenated 174 00:12:38,650 --> 00:12:39,483 together. 175 00:12:40,060 --> 00:12:45,060 But the problem occurs on the next step because we wanna compare the love score 176 00:12:45,850 --> 00:12:50,380 against an actual number, then if it's a string, 177 00:12:50,770 --> 00:12:54,670 it's not going to work. So in order to solve this, 178 00:12:55,120 --> 00:12:59,830 then we actually have to convert the love score into an integer. 179 00:13:00,130 --> 00:13:02,200 So you could use a separate step. 180 00:13:02,440 --> 00:13:06,220 So the int_score equals int 181 00:13:06,910 --> 00:13:11,830 and then we wrap it around the love score. Alternatively, um, 182 00:13:11,920 --> 00:13:16,920 and a lot easier is to simply just wrap that whole line inside a set of brackets 183 00:13:19,120 --> 00:13:22,660 and convert the whole thing into an integer on the same line. 184 00:13:23,110 --> 00:13:27,220 It depends on how comfortable you are with this code as to which option you'll 185 00:13:27,220 --> 00:13:29,830 choose. Now that we're done here, 186 00:13:29,830 --> 00:13:33,880 let's go ahead and run our code again and let's just check it out. 187 00:13:38,280 --> 00:13:41,130 Your score is 42. You are all right together. 188 00:13:41,550 --> 00:13:46,550 So now our code seems to be working and we've now completed this code challenge. 189 00:13:47,520 --> 00:13:50,310 How did you get on with this challenge? 190 00:13:50,400 --> 00:13:53,070 Did you manage to get everything right? 191 00:13:53,460 --> 00:13:55,950 Did you get stuck at certain places? 192 00:13:56,850 --> 00:14:01,440 Have a think about which parts of this challenge were the hardest and see if you 193 00:14:01,440 --> 00:14:05,280 can review some of those concepts so that the next time you encounter them, 194 00:14:05,340 --> 00:14:07,410 you'll be able to tackle them with confidence. 18929