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OK we'll come back.

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So it's time for a few javascript array exercises the way that this works.

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There's two exercises in both of them.

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I give you some code.

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All you need to do is evaluate what happens when this code is run.

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So here's the first one.

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Go ahead take a look.

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Pozza video if you need to and I'll go over the solution and just a few seconds.

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OK.

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So this one is a little bit tricky.

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We start by defining a numbers array.

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It has five numbers in it.

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And then we're printing out something from the numbers array numbers bracket numbers hotlink.

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So numbers that length in this case is 5 1 2 3 4 5 items.

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So we're going to access numbers bracket 5 which is a problem because the greatest index in this array

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is actually 4.

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We start at 0 1 2 3 4.

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So numbers 5 doesn't exist.

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So what we actually get is undefined and I'll show that to you.

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Paste this in the con. And we get undefined.

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Just like if I tried to do numbers of 100 that definitely doesn't exist and I get undefined.

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So if I do numbers of 5 I get undefined or do numbers of I get 88 so I want to a little bit tricky.

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So here's the second exercise positivity if you need to evaluate the code and then we'll go over solution

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and just a few moments.

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So this one looks a little bit scarier.

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We have nested arrays.

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So this outer array called friend groups has three items and each one is actually its own array.

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So this is what we call nested arrays or a two dimensional array because we're nesting in array instead

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of another array.

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So each one is three strings long three different friend groups from Harry Potter and I'm con. that

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logging friend groups.

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The third item index of 2.

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So that's going to retrieve this whole array right here.

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And then we're finding the first item index zero in that array which is Mouni.

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So I'm going to copy this into my console and demonstrate that if I look at friend groups of two that's

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going to give me this last friend or peer.

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And then if I take that and I get the zero index of that I get the first item which is Mouni.

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So this is pretty common to need to burrow into an array and then another array to have some nested

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data where we have to access the first layer.

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Friend groups to which then gives us this and then we have to then access that with index zero to get

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money out when we get to some more complicated data structures like the data that the Facebook API gives

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us or the data that comes from our Mongo DB database.

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Well need to burrow down into nested arrays to access our data.

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All right so that's it for these quick exercises