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All right, so we've done a raise, we've done sets, there's one other collection there, a few other



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collections actually, but one other collection that's quite important that we use fairly often.



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And this is called a dictionary.



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Now, if you think of a regular dictionary, it's ordered by letter, right?



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So it's got an alphabetical order to it.



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But one of the features that it has is that if you go to the section marked A you have all the words



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with A and that's exactly exactly the definition of a dictionary in programming as well.



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So if I just drop one here, we can define it by saying var dictionary has a type of character Kolon



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string.



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Right.



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So what I'm doing here is giving it a key, which is the letter A and then a value, which is the word



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apple.



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I could also if I wanted to give it an array of strings and that would actually cover an entire dictionary.



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So what have I got in my notes here?



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Oh yes, I have a better dictionary so I can paste this in better dictionary.



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And in this case, I've got a character which is just one letter and I have an array of strings.



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Right.



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So that's how you declare an array.



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And then I'm saying in this dictionary, I want you to put under way.



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And that's represented by this code on Apple and Aardvark writes, We're well on our way to building



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a dictionary.



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It reminds you of an episode of Blackadder that I've really enjoyed where Baldrick had to write the



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dictionary and they went to the letter B and he went big blue wobbly thing what mermaids live in.



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I got to watch that actually.



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Right.



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So how do we add stuff to our dictionary?



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Well, better DECT sounds a bit rude.



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I know we want to access the element a right to the section on the A and what do we want to do.



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Well we want to append something to it now.



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We discussed options, which is the question mark symbol.



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A dictionary might not have a inside it, so we have to put a question mark here.



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So if our system doesn't find a it doesn't continue past this point, you can use if statements to check



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if everything's OK, then we're going to put DOT.



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And first thing that comes up is append.



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That is correct.



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We're going to add something to this section.



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What are we going to append?



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Well, I forgot, so let's add amnesia.



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Now we have our better dictionary with Apple, Aardvark and Amnesia, and I'll prove it to you.



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By doing the following.



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There we have it, Apple, Aardvark and amnesia.



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So that's a dictionary we could do the same with B, C, D, E, F, or we could do the same with music



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types or whatever you can imagine is required with a dictionary type of array or collection is a better



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word to use for that.



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Right.



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If I wanted to add B to it, we will do that.



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We can just go ahead and create that so it doesn't need to exist immediately, right?



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But when this case, we're not going to append anything, we're actually going to create it.



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B.



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In your Bonnett.



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And so now if I print that Benedict.



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We should get Bee has been Bonnett and a has Apple, Aardvark and amnesia, and of course you can go



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on and on like this now.



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You wouldn't ever use a dictionary in such a primitive way by just shoving strings into it.



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You'd actually have some sort of structure around this in a commercial application.



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But this shows you the concept quite well, right?



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A bit of homework.



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Oh, or because it's less than 10 and you've had two breaks from homework already make a dictionary



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that holds names of students by age.



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Right, so that's not that straightforward, again, if it sounds difficult.



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Stop right on a piece of paper.



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What do you think you should do and then translate that to code?



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Good luck.