Perl, convert hash to array

arrayshashperl

If I have a hash in Perl that contains complete and sequential integer mappings (ie, all keys from from 0 to n are mapped to something, no keys outside of this), is there a means of converting this to an Array?

I know I could iterate over the key/value pairs and place them into a new array, but something tells me there should be a built-in means of doing this.

Best Answer

If your original data source is a hash:

# first find the max key value, if you don't already know it:
use List::Util 'max';
my $maxkey = max keys %hash;

# get all the values, in order
my @array = @hash{0 .. $maxkey};

Or if your original data source is a hashref:

my $maxkey = max keys %$hashref;
my @array = @{$hashref}{0 .. $maxkey};

This is easy to test using this example:

my %hash;
@hash{0 .. 9} = ('a' .. 'j');

# insert code from above, and then print the result...
use Data::Dumper;
print Dumper(\%hash);
print Dumper(\@array);

$VAR1 = {
          '6' => 'g',
          '3' => 'd',
          '7' => 'h',
          '9' => 'j',
          '2' => 'c',
          '8' => 'i',
          '1' => 'b',
          '4' => 'e',
          '0' => 'a',
          '5' => 'f'
        };
$VAR1 = [
          'a',
          'b',
          'c',
          'd',
          'e',
          'f',
          'g',
          'h',
          'i',
          'j'
        ];
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