#!/usr/bin/perl -w

use strict;

my $arr = ['A -4 C','C -4 B','B -4 A','A -2 C','C -3 B'];


my @a = do {
    my $idx = 0;
    map {
        {
            data => [ split ' ', $_ ],
            idx  => $idx++,
        }
    }@$arr
};

use Data::Dumper;
print Dumper(\@a);

##</code><code>##

$VAR1 = [
          {
            'idx' => 0,
            'data' => [
                        'A',
                        '-4',
                        'C'
                      ]
          },
          {
            'idx' => 1,
            'data' => [
                        'C',
                        '-4',
                        'B'
                      ]
          },
          {
            'idx' => 2,
            'data' => [
                        'B',
                        '-4',
                        'A'
                      ]
          },
          {
            'idx' => 3,
            'data' => [
                        'A',
                        '-2',
                        'C'
                      ]
          },
          {
            'idx' => 4,
            'data' => [
                        'C',
                        '-3',
                        'B'
                      ]
          }
        ];

##</code><code>##

my @a = do {
    my $idx = 0;
    map {
        [ (split ' ', $_), $idx++ ],
    }@$arr
};