Generally, this is a combinatorial problem and there are modules to handle that. Here's another way which is only practical due to the small length of the entry. I run the combinations through hash keys to uniquify them. The regex match serves to both extract the digits and validate the input.

#!/usr/bin/perl -w
# filename: combo
use strict;

my $entry = shift;

my @array =
    $entry =~ m/^(\d)(\d)(\d)$/ ?
    ($1.$2.$3, $1.$3.$2, $2.$1.$3, $2.$3.$1, $3.$1.$2, $3.$2.$1) :
    ();

@array or die "Bad input: ${entry}\n";

@array = do {
    my %hash;
    @hash{@array} = ();
    keys %hash;
};

print "${entry} was entered.",
    " The different combinations would be @{array}.\n";

__END__
$ perl combo 123
123 was entered. The different combinations would be 231 123 312 321 2
+13 132.
$ perl combo 122
122 was entered. The different combinations would be 221 212 122.

[download]

You will be better off with an array instead of distinct named variables. It will accomodate the smaller number of combinations that are possible with duplicated digits, and you don't have to make up meaningful names for unmeaningful distinctions. (Yes, @array and %hash are not meaningful names outside tutorial use ;-)

After Compline,
Zaxo

In reply to Re: Getting combinations from a number's digits by Zaxo
in thread Getting combinations from a number's digits by PerceptiveJohn

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