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### Re^3: sort hash of arrays of arrays

by BrowserUk (Pope)
 on Oct 31, 2012 at 15:16 UTC ( #1001683=note: print w/replies, xml ) Need Help??

in reply to Re^2: sort hash of arrays of arrays
in thread sort hash of arrays of arrays

How can I do the sort based on the 2nd item of the innermost array?

Okay. So you have a hash of arrays of arrays; something like this:

```{
1 => [
[1, 2, 3],
[6, 7, 8],
[16, 17, 18],
[26, 27, 28]
],
2 => [
[2, 3, 4],
[7, 8, 9],
[17, 18, 19],
[27, 28, 29]
],
3 => [
[3, 4, 5],
[8, 9, 10],
[18, 19, 20],
[28, 29, 30]
],
4 => [
[4, 5, 6],
[9, 10, 11],
[19, 20, 21],
[29, 30, 31]
],
}

The second item of which innermost array?

Each outer array contains multiple arrays. Which of those do you which to sort on? The first? The last? All of them?

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

Replies are listed 'Best First'.
Re^4: sort hash of arrays of arrays
by maladav (Initiate) on Oct 31, 2012 at 15:49 UTC

I'd like to sort the outer arrays of each hash item (1-4) separately, based on the second item of the inner arrays to finally have something like:

```{
1 => [
[26, 27, 28],
[16, 17, 18],
[6, 7, 8],
[1, 2, 3]
],
2 => [
[27, 28, 29],
[17, 18, 19],
[7, 8, 9],
[2, 3, 4],
],
3 => [
[28, 29, 30],
[18, 19, 20],
[8, 9, 10],
[3, 4, 5]
],
4 => [
[29, 30, 31],
[19, 20, 21],
[9, 10, 11],
[4, 5, 6]
],
}

So for the first set, values 2, 7, 17 and 27 were compared to get the right order.
I hope this clarifies my problem.

Thanks

Then you need to do one sort for each key in the hash like this:

```@{ \$hash{\$_} } = sort{ \$b->[1] <=> \$a->[1] } @{ \$hash{\$_} } for keys %
+hash;;

pp \%hash;;
{
1 => [[26, 27, 28], [16, 17, 18], [6, 7, 8], [1, 2, 3]],
2 => [[27, 28, 29], [17, 18, 19], [7, 8, 9], [2, 3, 4]],
3 => [[28, 29, 30], [18, 19, 20], [8, 9, 10], [3, 4, 5]],
4 => [[29, 30, 31], [19, 20, 21], [9, 10, 11], [4, 5, 6]],
}

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

It's awesome, thank you!
How does it work? Specifically, why does it need the for keys %hash part? How could I sort on the innermost elements (e.g. [26, 27, 28] to get [28, 27, 26]) using the same method?
Thanks very much.

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