Original subtitles

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Let's continue with some simple string methods. 2

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And the first two are gonna be 3

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for changing the case of a string. 4

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So that's airline.to lowercase. 5

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And this doesn't require any arguments at all. 6

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And then we also have to uppercase. 7

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And these we use all the time, 8

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as you will see soon in a more real world example. 9

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And here you see that indeed, they transform to string, 10

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all to lowercase, and to uppercase. 11

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And again, you can of course, call these directly, 12

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also on a string, so like this, all right? 13

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But now let's use this on a more practical example, 14

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to fix the capitalization in a passenger name. 15

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capitalization in name, okay? 16

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So let's say that the passenger when he checked in 17

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I misspelled his name, and so it looks like this now. 18

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And so this needs to be fixed, 19

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it should look like this, okay? 20

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So in order to fix it, the first step is usually 21

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to put everything into lowercase here. 22

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So const, passenger, lower 23

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is passenger.to lowercase, like this. 24

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Okay, so basically, we already have now this part here. 25

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And now all we need to do is to essentially 26

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take the first letter, and then the rest of the string 27

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and put these two parts back together. 28

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So passenger, correct, will be passenger lowercase. 29

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And here, we only need the first letter. 30

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So how do we do that, 31

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we take the first letter by using the index zero. 32

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And so this one, we now convert to uppercase, all right? 33

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And now we simply need to add the rest of the string. 34

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So, again, we take passenger lower, 35

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and then we use the slice that we learned 36

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in the last lecture, and start at position number one, 37

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because remember, that will then go to index one, 38

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and take everything until the end of the string. 39

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And so here, we then put back together, 40

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just the first part of the string 41

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converted to uppercase here, and then the rest of the string 42

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that we already had converted to lowercase before. 43

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Now, okay, and, indeed, now it is corrected, great. 44

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And of course, we could have done a function with this. 45

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And so maybe if you have the time, you can do that. 46

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So just create a function which takes any passenger name, 47

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and then returns the correct one. 48

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So with the fixed capitalization, but anyway, 49

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I will now do another real life example, 50

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which is to check a user input email, okay? 51

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So check email, now, this will not be really a checking, 52

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it will more be a comparing, so comparing emails. 53

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So let's say that we have to email of one passenger. 54

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So hello at Jonas.io, but now as the user logs in, 55

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so let's say login email, accidentally they do it all wrong, 56

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and they start with a couple of spaces here, 57

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and then the capitalization is all completely off 58

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like this, and then maybe even another space, 59

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or even an enter character, which remember is backslash n. 60

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So I think we talked about that in the beginning, okay? 61

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But still, this email here is actually still kind of correct 62

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and kind of valid. 63

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And so we can now still compare 64

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if these two are kind of the same, okay? 65

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So we can now try to convert this one to this one, 66

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and then check if they are the same. 67

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Because essentially, again, they are, 68

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they would be different if we had 69

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like different letters here, then of course, 70

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they would not be the same. 71

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But here it's just a matter of capitalization. 72

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And for emails I believe that they are still valid 73

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even with the capitalization off. 74

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And so when we check user input like this, 75

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the first step is usually to convert it to lowercase. 76

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So lower email, is login email.to lowercase. 77

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And then we must also get rid of all the whitespace here. 78

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So these empty spaces, and also this enter basically here 79

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also counts as a whitespace. 80

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So there is even a method for that. 81

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So let's say, trimmed email. 82

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And so that is lower email.trim. 83

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All right, let's just now log this to the console 84

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just to see. 85

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And so that looks exactly like that first version. 86

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Now, just look closely at what we did here. 87

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So we called to lowercase on this login email, 88

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stored it to this variable, 89

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and then on that variable, we called the trim method. 90

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But why do we even need this intermediate email?