1 00:00:05,380 --> 00:00:07,150 Welcome back everyone in this lecture. 2 00:00:07,180 --> 00:00:09,750 We're going to go through the solutions for the function tasks. 3 00:00:09,760 --> 00:00:10,700 Let's get started. 4 00:00:10,990 --> 00:00:11,230 OK. 5 00:00:11,230 --> 00:00:14,090 Let's begin by taking a look at task one. 6 00:00:14,110 --> 00:00:18,300 So the first one I wanted you to return a boolean to check if there's some of these two numbers was 7 00:00:18,310 --> 00:00:19,630 equal to 10. 8 00:00:19,720 --> 00:00:21,370 Often beginners will do something like this. 9 00:00:21,370 --> 00:00:32,930 They'll say if and one plus and two is equal to 10 return TRUE else return false. 10 00:00:32,930 --> 00:00:37,760 Now while this is a perfectly valid solution it's actually not the most efficient solution because remember 11 00:00:37,760 --> 00:00:43,700 just like we showed in some previous lectures this itself is already the boolean true or false. 12 00:00:43,700 --> 00:00:51,470 So instead of doing something like this you could just return there some if it's equal to 10 or not. 13 00:00:51,500 --> 00:00:53,050 So you could take the sum first. 14 00:00:53,090 --> 00:00:59,750 So we'll say OK and one plus and two and check if this sum is equal to the number 10 and I'll return 15 00:00:59,750 --> 00:01:00,190 a boolean. 16 00:01:00,200 --> 00:01:01,220 True or false. 17 00:01:03,180 --> 00:01:06,390 Moving on to task 2 wanted to check 10 some. 18 00:01:06,420 --> 00:01:08,280 So this one was a little different. 19 00:01:08,300 --> 00:01:12,840 Now you are going to need some sort of if statement because I want you to first check if the sum is 20 00:01:12,840 --> 00:01:23,560 equal to 10 return TRUE else return there are some so say if and one plus two is equal to 10 return 21 00:01:24,040 --> 00:01:32,930 TRUE else will return their actual sum or turn and one plus and two OK. 22 00:01:33,180 --> 00:01:36,730 So again now we actually do need that if statement. 23 00:01:36,740 --> 00:01:42,320 Now let's return to task 3 and this one wanted you to create a function that takes in a string and returns 24 00:01:42,320 --> 00:01:45,040 back the first character of that string in uppercase. 25 00:01:45,050 --> 00:01:46,300 This is pretty straightforward. 26 00:01:46,310 --> 00:01:53,250 All we need to do is say my string grab the first character which is going to be 0 and then perform 27 00:01:53,250 --> 00:01:55,610 the upper on it and just return that result. 28 00:01:56,880 --> 00:01:58,280 OK that's all you have to do for that one. 29 00:01:58,280 --> 00:02:01,170 Just again grabbing the first character and then calling the upper. 30 00:02:01,170 --> 00:02:06,560 You could technically separate this out into two steps but you can also do it all in one step OK. 31 00:02:06,560 --> 00:02:11,360 Moving along to task for this one wanted you to create a function that takes in a string and returns 32 00:02:11,360 --> 00:02:12,860 the last two characters. 33 00:02:12,860 --> 00:02:17,420 Now there was a stack overflow alink that give you a pretty good answer on how to actually grab characters 34 00:02:17,420 --> 00:02:19,960 from the end more than just one character from the end. 35 00:02:20,210 --> 00:02:22,100 So let's walk through how we could do this. 36 00:02:22,100 --> 00:02:26,640 First we should be checking at the length the string is less than two. 37 00:02:26,780 --> 00:02:41,330 So I'll say if length of my string is less than 2 return error else and this is where you could use 38 00:02:41,330 --> 00:02:49,220 that stack overflow alink we're going to return my string starting index position negative to essentially 39 00:02:49,220 --> 00:02:53,140 two steps back from the end colon all the way to the end. 40 00:02:53,180 --> 00:02:56,930 So if you take a look at the stack overfilling it would have given you this sort of syntax. 41 00:02:56,930 --> 00:03:01,760 So this isn't something we exactly covered in our string lecture but it is something you would be able 42 00:03:01,760 --> 00:03:04,120 to figure out if you used this link. 43 00:03:04,470 --> 00:03:04,740 OK. 44 00:03:04,760 --> 00:03:09,800 Again just going back from the very end to spaces and then colon go all the way to the end. 45 00:03:09,800 --> 00:03:18,220 So our starting position here is necklet to task number five was given a list of integers return true 46 00:03:18,340 --> 00:03:21,700 is the sequence 1 2 3 is somewhere in the list. 47 00:03:21,730 --> 00:03:25,290 So this one probably has the most variety of ways you can tackle this problem. 48 00:03:25,300 --> 00:03:26,700 Lots of different ways to do it. 49 00:03:26,710 --> 00:03:28,940 I'll show you one simple way. 50 00:03:29,050 --> 00:03:34,560 So one way to do this is we can iterate through the list all the way up to the last two. 51 00:03:34,570 --> 00:03:41,660 So we're going to say for I in range length of Nom's minus two 52 00:03:45,140 --> 00:04:01,330 numbs of I is equal to 1 and number of I plus 1 is equal to 2 and Nom's of E-plus to is equal to three 53 00:04:02,880 --> 00:04:10,380 then return true otherwise otherwise we'll just return false. 54 00:04:10,560 --> 00:04:15,330 So let me zoom out here just we can kind of see what's going on. 55 00:04:15,340 --> 00:04:20,990 So again what I'm doing here is going to say for every i in range length of Nom's minus two. 56 00:04:21,280 --> 00:04:26,140 So what this is doing and I'll probably make more sense if we look at this line first let's imagine 57 00:04:26,140 --> 00:04:30,250 what it is just going to be the index positions themselves. 58 00:04:30,580 --> 00:04:32,600 So this for loop right here. 59 00:04:32,770 --> 00:04:40,730 That's going to start at zero than 1 One two three and it's go all the way until the length of the list. 60 00:04:40,960 --> 00:04:42,120 Minus two. 61 00:04:42,280 --> 00:04:44,410 And often beginners get confused Well why not. 62 00:04:44,410 --> 00:04:46,910 All the way to the length list why minus two. 63 00:04:47,020 --> 00:04:52,340 And that's because those what we're doing in this line we're saying if none of AI is equal to 1. 64 00:04:52,390 --> 00:04:57,880 So if in that list of numbers in addition is equal to 1 and the very next index to an AI plus one is 65 00:04:57,880 --> 00:05:01,630 equal to two and then next to this and after that I plus two is equal to three. 66 00:05:01,630 --> 00:05:02,600 Well then you have your match. 67 00:05:02,620 --> 00:05:04,540 You're going to return true. 68 00:05:04,540 --> 00:05:08,280 Now the trick is we're saying I plus 1 and I plus 2. 69 00:05:08,320 --> 00:05:12,960 That means we only need to go in this range up to and minus 2. 70 00:05:12,970 --> 00:05:15,120 We don't need to go all the way to the end of that list. 71 00:05:15,190 --> 00:05:20,460 Otherwise I plus one and I plus two would be reaching out beyond the length of the list. 72 00:05:20,470 --> 00:05:26,580 So that's why we say length of numbers minus two because we have I plus two and I plus 1. 73 00:05:26,650 --> 00:05:31,600 So we don't need to go all the way to the end of the list and said we need to go to up to the analyst 74 00:05:31,630 --> 00:05:37,180 because I plus 1 I plus two themselves will reach the end of the list and then if this happens to be 75 00:05:37,180 --> 00:05:39,290 the case 1 2 and 3. 76 00:05:39,650 --> 00:05:41,450 Well then you can just return true. 77 00:05:41,710 --> 00:05:45,640 Then if you've gone through this entire four loop and you never returned to true then I'm just going 78 00:05:45,640 --> 00:05:46,690 to return false. 79 00:05:46,690 --> 00:05:51,740 So notice how my for loop is now indented at the same as it's return false. 80 00:05:51,760 --> 00:05:52,330 OK. 81 00:05:52,390 --> 00:05:54,650 There's lots of other ways you get done this sequence check. 82 00:05:54,660 --> 00:05:56,790 Maybe you could have just done this as a single slice. 83 00:05:56,950 --> 00:06:00,400 So Gone slice by slice and then check it to be the list. 84 00:06:00,400 --> 00:06:05,010 One two three but I think this is the most kind of fundamental way of doing it. 85 00:06:05,010 --> 00:06:09,080 Yes go throughout the list and then check three at a time separately and return true. 86 00:06:09,100 --> 00:06:10,370 They happened to be the case. 87 00:06:10,390 --> 00:06:12,960 The trick here being you have to go all the way to the end of the list. 88 00:06:12,970 --> 00:06:20,200 You just have to go to the length of the list minus two because of this I plus one and I plus two OK. 89 00:06:20,210 --> 00:06:25,540 Let's move on to task number six which was given two strings create a function that returns a length. 90 00:06:25,640 --> 00:06:27,620 The difference in length between them. 91 00:06:27,640 --> 00:06:31,010 This it's actually pretty straightforward if were able to figure out how to do an absolute value in 92 00:06:31,010 --> 00:06:35,270 Python which in this case was just abs. 93 00:06:35,280 --> 00:06:41,700 So first we take the length of string 1 which here we called S1 and then we subtract the length of S 94 00:06:41,760 --> 00:06:42,580 2. 95 00:06:42,600 --> 00:06:46,760 So this right here this gives you the difference in length between S1 and S2. 96 00:06:46,950 --> 00:06:51,350 However if one is smaller than as two then you'll get a negative number. 97 00:06:51,370 --> 00:06:54,730 So you're going to want to return the absolute value of this difference. 98 00:06:54,750 --> 00:07:04,320 So then you just pass it into abs absolute value and then you just return that and that is your solution. 99 00:07:04,540 --> 00:07:12,030 So we turn the absolute value between the difference of length of these two strings finally task number 100 00:07:12,030 --> 00:07:15,800 seven given a list of integers is the length but the list is an even number. 101 00:07:15,900 --> 00:07:20,940 Return the sum of that list is the length of the list is odd return the max value in that list. 102 00:07:21,210 --> 00:07:22,320 So how can we do that. 103 00:07:23,640 --> 00:07:29,790 Well we can say length is equal to length of my list. 104 00:07:31,460 --> 00:07:32,460 And then we'll say the following. 105 00:07:32,510 --> 00:07:37,670 If the length mod to is equal to zero. 106 00:07:38,450 --> 00:07:48,520 Return the sum of the list else return the max of my list. 107 00:07:48,810 --> 00:07:54,450 So all we're doing here is we're checking the length of that list saying if the length Mattu is equal 108 00:07:54,450 --> 00:07:56,530 to zero then return the sum. 109 00:07:56,520 --> 00:08:01,390 Otherwise just return the max of the list and that's the sum or max function. 110 00:08:01,760 --> 00:08:03,650 Ok that's it for this lecture. 111 00:08:03,690 --> 00:08:06,690 I hope you found the section useful if you're a beginner to Python. 112 00:08:06,690 --> 00:08:11,920 Coming up next we're going to begin to discuss more advanced Python topics in Python level 2. 113 00:08:12,000 --> 00:08:15,060 If you have any questions feel free to post the Q&A forums. 114 00:08:15,060 --> 00:08:16,020 We'll see you there.