Re: Re: Character Combinations

[Limbic~Region]

in reply to Re: Character Combinations
in thread Character Combinations

chunlou,
Permutations are not combinations. For instance - say I wanted to find all combinations of 4 character strings with each position able to be 26 different letters. This is what I believe is being asked for. I am pretty sure there is an iterative solution - but all I can come up with right now are recursive ones.

Cheers - L~R

[chunlou]

You mean this?

use Algorithm::FastPermute;
my @c = ('a'..'c');
for my $i (0..2) {
    for my $j (0..2) {
        my @c = @c[$i..$j] if $i <= $j;
        permute {print @c , "\n"} @c;
    }
}

__END__
a
ab
ba
abc
acb
cab
bac
bca
cba
b
bc
cb
c

[Limbic~Region]

chunlou,
Considering that missed ca - no. It also doesn't work if you change
my @c = ('a'..'c');
to
my @c = ('a'..'z');

Permutations are not combinations.

L~R

[chunlou]

Silly me. Should have consulted with this: Permutations and combinations.

use Algorithm::FastPermute;

sub combinations {
  return [] unless @_;
  my $first = shift;
  my @rest = combinations(@_);
  return @rest, map { [$first, @$_] } @rest;
} 

for(combinations('a'..'c')){
    my @c = @{$_};
    permute {print @c , "\n"} @c;
}

__END__
c
b
bc
cb
a
ac
ca
ab
ba
abc
acb
cab
bac
bca
cba