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Let's take a look at a dictionary comprehension.

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So a dictionary comprehension is a lot like a list comprehension,

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but instead of having a for loop that could be 3, 4, 10

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lines of code, we have it basically set up in one line of

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code. So let's go through the long way, and then let's go

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through the short way, which is a dictionary comprehension.

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So as an example, let's say we have a list of 'keys', and we've

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got a 'name', and 'age', and a 'role';

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and then we've got a list of 'values' in here as well.

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And I'm going to put in just my information here, and I am a 'Teacher'.

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So what I could do, is I could create an empty dictionary called 'person',

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and I could say 'for key, value in zip(keys, values)',

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Remember, 'zip' is going to take these two lists and merge

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them together in a paired tuple.

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So it's going to be - 'name' with 'Kalob'; 'age' - 30; 'role' as 'Teacher'.

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And then I could say, 'person[key] = value',

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and when we print this out, we have a dictionary 'person' with

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the key of 'name' is 'Kalob'; key of 'age' - 30; key of 'role' is 'Teacher'.

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And let's just verify this is in fact a dictionary.

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We can see that it is by how its syntax looks, just like this.

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But just to be fair, we know that it's a dictionary.

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Now, this is a very small example,

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but what we could do instead is put this all into one line.

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Well, not all of it.

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We can't put this into one line.

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Those need to be pre-existing because they're variables we're going

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to use inside of the 'zip' function.

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So what we could do here, is let's say 'person2' so that

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we don't overwrite the original 'person' here.

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'person2 = {',

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and what I'm going to do is actually put this on a new line,

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just because I like to put this on a new line sometimes to

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make it a little more readable.

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And then I'll put it on a single line

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if it's short enough. If your list comprehensions or your

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dictionary comprehensions ever get too long, feel free to

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put them on multiple lines, that's okay.

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And so what we want to do here is write our for loop.

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So 'for key, value in zip(keys, values)',

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Now, in a list comprehension, we would really just say 'key',

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'key for key, value in zip',

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and this is what it's returning.

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But a dictionary has a 'key' and a 'value' in it, and you can

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actually see that it's got a little cool in here.

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So this is your 'key', this is your 'value'.

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We do the same thing in a dictionary comprehension.

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'key: value'.

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And let's go ahead and just put this back all on one line.

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And let's run this, 'person2', it's the exact same thing as what

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we wrote up here.

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Now we could even add 'if' statements as well.

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So let's go ahead and create 'person3',

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but let's say we didn't want the 'role' in there.

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We could say 'if', at the very end of this, the 'key ==

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age', we could get just the 'age', or we could do the inverse

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and we could say, only ever do this if the 'key != age'.

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So it's just going to return 'name' is 'Kalob', and 'role' is 'Teacher'.

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We're going to jam that into person number three,

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[no audio]

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and 'person3'. Bam.

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We have now just looped over 'keys' and 'values' in two different

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lists, merged them together, and down here

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what we said was, if that key, if that key up here is 'age', skip it.

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Otherwise, if the key is anything else, if the key equals

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literally anything else that does not match 'age', then add

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it to your dictionary.

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And that is a dictionary comprehension.

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So what I would like you to do is get a little bit of experience with this one.

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Dictionary comprehensions are a little less commonplace than

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a list comprehension, but it's still wildly valuable in Python,

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and you're going to run into these anyway, so you might as

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well get some practice with it now.

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So go ahead, give this a shot.

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Don't forget, you can always download this Jupyter Notebook as well, and

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play around with my code.

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And once you think you have the hang of it, let's go ahead

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and start that next lesson.