String Indexing

Quick reference

• 00:03 Okay, in this video I want to talk about string indexing.
• 00:07 And string indexing is determining how many things are in your string.
• 00:12 So how many characters, and manipulating them based on that number.
• 00:17 And there's all kinds of different reasons why you might want to use
• 00:19 something like this.
• 00:20 And it's actually pretty easy to do.
• 00:22 So let's just jump in here and create a string and
• 00:25 we'll call it myString again and set that equal to my name is John Elder, all right.
• 00:33 And if we want to print this out, we can.
• 00:38 If we save this and run it really quick,
• 00:39 we know that this is going to return my name is John Elder.
• 00:42 Well, with a string, each character is a number and
• 00:47 they start at zero, so m is zero, y is one,
• 00:52 this space is two, n is three, and so on and so on.
• 00:57 And we can reference them using square brackets, and
• 01:00 we could just pass in the number that we want.
• 01:02 So for instance, if we say print out the zeroth item of our string,
• 01:07 zeroth index number, we could do that.
• 01:10 If we save this and run it, it should just return M.
• 01:12 And sure enough, it does, M, right?
• 01:16 So okay, why is that useful?
• 01:18 Well, like I said, there are lots of times when you need to
• 01:21 know how many characters are in your string.
• 01:24 Maybe you want to replace certain things, maybe you want to remove certain things.
• 01:29 We talked about in the last video different string functions.
• 01:33 There is a remove function, right?
• 01:36 So we can call that and say .remove and then inside of here we can
• 01:42 pass in a number so 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
• 01:47 So we say, hey, everything after the tenth item in our index, remove that.
• 01:51 So if we save this and run it, we see my name is and nothing else.
• 01:57 So that's kind of cool we might need to know the length so L-E-N-G-T-H.
• 02:03 Now this actually doesn't require parentheses so we can .length,
• 02:08 type this down.
• 02:09 And this will return how many characters this string is, so
• 02:14 save this and run it, and we see 21, very cool.
• 02:19 And now let's confirm this.
• 02:22 So let's go 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
• 02:27 21, right?
• 02:29 So the length of this is 21.
• 02:32 The index number doesn't start with one.
• 02:35 You see how I started counting?
• 02:37 Same thing with remove, the index number always starts at zero but for
• 02:40 counting purposes we count like normal, which is a little bit confusing, right?
• 02:44 So like I said, this is 21 characters.
• 02:47 This r is the 20th index number, though, right?
• 02:51 That's a little confusing.
• 02:52 Why is that?
• 02:53 Because like I said it starts at 0, so M is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
• 02:58 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, right?
• 03:03 So there are 20 index numbers, but 21 characters, if that makes sense.
• 03:09 So that's string indexing,
• 03:11 just sort of remember it's a way to find out how many characters in your string and
• 03:15 how to do things inside the string based on the number.
• 03:19 Like I said, we can remove everything after the 10th item,
• 03:22 so my name is, everything else gets removed, and that's all there is to it.
• 03:26 So in the next video we're going to look at string concatenation and interpolation.

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