1 00:00:00,630 --> 00:00:02,250 Instructor: All right, in this exercise, 2 00:00:02,250 --> 00:00:05,550 we're going to be doing some dictionary comprehension. 3 00:00:05,550 --> 00:00:09,030 What we have is in the input a sentence 4 00:00:09,030 --> 00:00:13,680 and when that sentence is passed in into your main.py, 5 00:00:13,680 --> 00:00:18,533 you're going to convert it into a list of words. 6 00:00:19,470 --> 00:00:24,470 And the list should contain each word in the sentence. 7 00:00:24,870 --> 00:00:28,590 And you're gonna use that list to then create a dictionary 8 00:00:28,590 --> 00:00:32,820 where you count the number of letters in each word. 9 00:00:32,820 --> 00:00:35,370 If you take a look in the description pane, 10 00:00:35,370 --> 00:00:38,400 you'll see what the example output should look like 11 00:00:38,400 --> 00:00:40,620 for the input sentence 12 00:00:40,620 --> 00:00:44,100 what is the airspeed velocity of an unladen swallow? 13 00:00:44,100 --> 00:00:46,650 And you'll notice that for simplicity's sake, 14 00:00:46,650 --> 00:00:50,880 we are counting all punctuation as a part of the word. 15 00:00:50,880 --> 00:00:54,480 So the swallow and question mark at the end 16 00:00:54,480 --> 00:00:57,240 of that example output dictionary is counted 17 00:00:57,240 --> 00:01:00,030 as eight and not seven. 18 00:01:00,030 --> 00:01:01,530 This is the goal 19 00:01:01,530 --> 00:01:03,270 and you're gonna need to use what you've learned 20 00:01:03,270 --> 00:01:05,700 about list and dictionary comprehension. 21 00:01:05,700 --> 00:01:07,080 You might have to google around to figure out 22 00:01:07,080 --> 00:01:11,010 how to turn a sentence into a list of words 23 00:01:11,010 --> 00:01:12,090 and you might need to check some 24 00:01:12,090 --> 00:01:14,790 of the hints to help you along the way. 25 00:01:14,790 --> 00:01:16,983 Have a go at this challenge. 26 00:01:20,640 --> 00:01:24,330 Similar to list comprehension, we start with the for loop. 27 00:01:24,330 --> 00:01:27,990 So notice that we are creating a dictionary comprehension 28 00:01:27,990 --> 00:01:29,640 and the only difference between dictionary 29 00:01:29,640 --> 00:01:32,130 and list comprehension is the symbol 30 00:01:32,130 --> 00:01:34,470 that goes around our code. 31 00:01:34,470 --> 00:01:36,210 For the list, it was the square bracket, 32 00:01:36,210 --> 00:01:38,403 for dictionary, it's the curly braces. 33 00:01:39,660 --> 00:01:42,810 The first thing we have is sentence.split 34 00:01:42,810 --> 00:01:46,350 and this is a Python method that can take a string 35 00:01:46,350 --> 00:01:47,910 and split it. 36 00:01:47,910 --> 00:01:52,230 Inside the split method, we can add an optional separator. 37 00:01:52,230 --> 00:01:56,370 So what do you wanna split the sentence by? 38 00:01:56,370 --> 00:01:59,040 And if you leave that empty, then it's going to split it 39 00:01:59,040 --> 00:02:01,590 by white space, which is what we have here. 40 00:02:01,590 --> 00:02:04,650 The space between each word is going to be used 41 00:02:04,650 --> 00:02:09,650 as the marker that is going to define each item in the list. 42 00:02:10,080 --> 00:02:13,350 Sentence.split basically takes our input sentence 43 00:02:13,350 --> 00:02:17,460 and then creates a list adding each item separated 44 00:02:17,460 --> 00:02:22,200 by white space as an individual new element in the list. 45 00:02:22,200 --> 00:02:24,750 And you can run the code at this point to see 46 00:02:24,750 --> 00:02:27,090 what that looks like if you haven't managed 47 00:02:27,090 --> 00:02:28,233 to get this to work. 48 00:02:29,070 --> 00:02:31,950 Now, the next step in our dictionary comprehension 49 00:02:31,950 --> 00:02:33,480 is our for loop. 50 00:02:33,480 --> 00:02:36,930 So we're saying for word in sentence.split, 51 00:02:36,930 --> 00:02:39,930 which means let's loop through each of the items 52 00:02:39,930 --> 00:02:42,840 in that list we've just created, and we're going 53 00:02:42,840 --> 00:02:45,720 to do something to each of the items in the list, 54 00:02:45,720 --> 00:02:49,650 which we can now access through this variable name word. 55 00:02:49,650 --> 00:02:52,770 Finally, at the beginning of our dictionary comprehension, 56 00:02:52,770 --> 00:02:55,200 we define what is going to go 57 00:02:55,200 --> 00:02:58,740 into our dictionary, the structure of it, if you will. 58 00:02:58,740 --> 00:03:01,050 It's going to have a key and value pair. 59 00:03:01,050 --> 00:03:04,110 The key is going to be the actual word. 60 00:03:04,110 --> 00:03:06,300 And notice this comes from our for loop. 61 00:03:06,300 --> 00:03:11,130 So this is equivalent to each item in our list. 62 00:03:11,130 --> 00:03:12,960 Every single word basically 63 00:03:12,960 --> 00:03:16,230 in the sentence is going to be a key 64 00:03:16,230 --> 00:03:19,140 and then the value comes after the colon symbol. 65 00:03:19,140 --> 00:03:24,090 And this is using the len method to calculate the length 66 00:03:24,090 --> 00:03:24,923 of that word. 67 00:03:24,923 --> 00:03:27,870 So how many characters are in that word 68 00:03:27,870 --> 00:03:32,520 and this entire line of code achieves that objective 69 00:03:32,520 --> 00:03:35,040 that we had in the beginning of the exercise, 70 00:03:35,040 --> 00:03:39,300 which is to create a dictionary by taking an input sentence 71 00:03:39,300 --> 00:03:43,860 and show us how many characters are in each word. 72 00:03:43,860 --> 00:03:45,870 And each word is separated 73 00:03:45,870 --> 00:03:50,130 as a separate key-value pair in our dictionary. 74 00:03:50,130 --> 00:03:52,500 Hopefully you managed to get this to work. 75 00:03:52,500 --> 00:03:55,530 If not, go back now and fix your code. 76 00:03:55,530 --> 00:03:58,710 Don't worry if you didn't manage to get it 77 00:03:58,710 --> 00:04:02,250 or you see the solution and it looks different. 78 00:04:02,250 --> 00:04:04,410 If your code managed to pass the test, 79 00:04:04,410 --> 00:04:06,240 then it has achieved the objective 80 00:04:06,240 --> 00:04:08,040 even if it looks different. 81 00:04:08,040 --> 00:04:09,600 But if your code didn't work, 82 00:04:09,600 --> 00:04:11,070 then this is the learning point. 83 00:04:11,070 --> 00:04:13,320 This is the time to fix it 84 00:04:13,320 --> 00:04:16,470 and get this skill into your tool belt. 85 00:04:16,470 --> 00:04:17,822 So don't worry about it.