Question

For example, I have an array

my @arr = qw(0 1 2 3 4);

How do I get the following combinations:

0
01
012
0123
01234
1
12
123
1234
2
23
234
3
34
4

If any, what’s the name for this kind of combination (or permutation)?

Thanks like always!

Answer 1

Use array slices:

#! /usr/bin/perl

use warnings;
use strict;

my @arr = qw(0 1 2 3 4);

my @result;
for (my $i = 0; $i < @arr; $i++) {
  for (my $j = $i; $j < @arr; $j++) {
    push @result => [ @arr[$i .. $j] ];
  }
}

print @$_, "\n" for @result;

Output:

0
01
012
0123
01234
1
12
123
1234
2
23
234
3
34
4