CODEWITHSUNDEEP
perlarrayssortingnumeric
user366121
user366121

Reputation: 3271

Sort Perl numeric array

I have an array which looks like this:

array[0]: 6 8
array[1]: 12 9 6
array[2]: 33 32 5
array[3]: 8 6

I want to sort this array so that it looks like this:

array[0]: 6 8
array[1]: 6 9 12
array[2]: 5 32 33
array[3]: 6 8

I know I can sort the array with @newarray = sort {$a cmp $b} @array;, but I need to sort the elements in each line as well. How can I do that?

Upvotes: 1

Views: 5247

Answers (3)

Telemachus
Telemachus

Reputation: 19705

Update 2021-03-16: Dear future visitors, I have the accepted answer, and I'm still getting upvotes, but @FMc's solution is clearly better than mine. (FMc and dalton have the same answer, but as far as I can tell, FMc got there first.)

In any case, if you have a situation like this use Perl's built-in map rather than my original answer of a custom subroutine.

Original answer: Assuming that you have an array of strings there, and that all you want is to sort each string as if it were a sub-array of numbers (but leave it a string?):

#!/usr/bin/env perl
use strict;
use warnings;

my @array = ('6 8', '12 9 6', '33 32 5', '8 6');

foreach my $string (@array) {
    $string = split_sort($string);
}

sub split_sort {
    my $string = shift @_;
    my @internal_nums = split ' ', $string;
    @internal_nums = sort {$a <=> $b} @internal_nums;
    return join ' ', @internal_nums;
}

print "@array\n";

Upvotes: 8

dalton
dalton

Reputation: 3696

You could also solve it using map:

#!/usr/bin/env perl

my @numbers = (
    '6 8',
    '12 9 6',
    '33 32 5',
    '8 6',
);

my @sorted;
push (@sorted, map { join " ", sort { $a <=> $b }  (split / /, $_) } @numbers);


print "$_\n" for @sorted;

Outputs:

6 8
6 9 12
5 32 33
6 8

Upvotes: 7

FMc
FMc

Reputation: 42411

You have a list of items that you want to transform. That's a perfect candidate for map. Also note the default behavior of split: it operates on $_, splitting on whitespace, after removing leading whitespace.

my @array = ('6 8', '12 9 6', '33 32 5', '8 6');
@array = map { join ' ', sort {$a <=> $b} split } @array;

Upvotes: 5

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