Hash Manipulation

Quick reference

• 00:04 We've got our hash, we've created it.
• 00:06 What if we want to add something later on, or remove something later on, to our hash?
• 00:10 That's what we're going to talk about in this video.
• 00:12 But before we do that, I just want to really quickly, let's puts out our
• 00:15 favorite _pizza, just puts this on the screen and see what happens.
• 00:18 Slightly different than our array, we get the actual sort of
• 00:21 objecty-looking thing itself, which is kind of interesting.
• 00:24 How do we manipulate our hash?
• 00:25 So let's say we want to add something to our hash later on.
• 00:29 We've already created it, it already exists.
• 00:31 Now, later on, we're like, I forgot something,
• 00:33 we want to put something else in, how do we do that?
• 00:35 Well, it's pretty simple, we just go favorite_pizza and then type in the key.
• 00:40 So let's say we want to add, who don't we have, Steve.
• 00:44 And Steve's favorite_pizza = "Hamburger", right?
• 00:49 So now we can puts our favorite_pizza to the screen just to see if it got added.
• 00:55 In fact, let's copy this, and let's put it before and after, so we can see.
• 01:02 So let's run this thing, you can see the first time we puts it out,
• 01:05 there's no mention of Steve.
• 01:07 But then we've added Steve here, and then, boom, there he is.
• 01:10 So pretty simple to do, that's all there is to it.
• 01:13 Now removing somebody is just as easy, we just use the delete method.
• 01:17 So let's come up here and copy this, and
• 01:20 let's say we don't want Steve in there after all.
• 01:24 So we just go call favorite_pizza again and then .delete.
• 01:30 And like I said before in the past, a lot of times when we want to do things in
• 01:34 Ruby, we just put a dot after the thing, that's an object-oriented type thing.
• 01:38 So this time, instead of the brackets, we're going to do these parentheses, so
• 01:43 let's go Steve.
• 01:44 Okay, so let's puts out our hash more time afterwards and
• 01:47 make sure Steve has been deleted.
• 01:49 So let's run this thing, so the first time, Steve's not there,
• 01:52 then we've added Steve, so he's listed.
• 01:54 Then we remove Steve, and then finally Steve is gone.
• 01:57 So that's how you add a thing to a hash,
• 01:59 that's how you delete a thing from a hash, very, very simple.
• 02:02 So if we want to o do this programmatically, we could go,
• 02:07 let's go print "Enter Your Name: And
• 02:11 then let's call my_name = gets.chomp,
• 02:17 and then print "Enter Pizza", and
• 02:22 then pizza = gets.chomp.
• 02:26 Okay, so now we can go favorite_pizza,
• 02:32 and pass in our my_name = pizza.
• 02:37 And now that that will add the user stuff we just gets-ed.
• 02:41 And then let's just puts out our favorite_pizza.
• 02:45 And in fact, I'm going to copy this, and let's put it up before as well, so
• 02:49 we can see the before and after.
• 02:51 So now if we run this, here's our original hash.
• 02:55 And let's enter Terry, and pizza, Terry likes tuna pizza, is that even a thing?
• 03:01 So then when our hash gets printed out again, now we see Terry likes tuna.
• 03:06 I can put a colon and a space there to make it nice.
• 03:10 But anyway, it's just that easy to add and remove things from a hash.
• 03:13 You can do it programmatically or you can do it with user input, however you'd like.
• 03:17 So that's hashes, that's hash manipulation, in the next video,
• 03:20 we're going to start looking at methods.

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