array combinations

azaria has asked for the wisdom of the Perl Monks concerning the following question:

Hello, I have several arrays, kets say:

@a1 = qw(0 1 2 3  4);
@a2 = qw(0 1 2 3 4 5 6 7 8);
@a3 = qw(0 1);
@a4 = qw(0 1 2 3 4 5);
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I would like to generates simply (without for loops) the all permutation strings (5 x 9 x 2 x 6 options)

$str = $a1[$i] . " " . $a2[$j] . " ". $a3[$k]. " " . $a4[$l]
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Any simple solution ? Thanks azaria

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Re: array combinations by moritz (Cardinal) on Jun 26, 2008 at 10:18 UTC
Set::CrossProduct does exactly that. You have to build one loop to get the strings, though. You can also make up something with glob. Update: here's an example with glob: `#!/usr/bin/perl use strict; use warnings; my @l = ( [1, 2, 3], [4, 5], [6, 7] ); my $glob = join '', map {'{'. join(',', @$_). '}'} @l; local $\ = "\n"; print for glob $glob; __END__ 146 147 156 157 246 247 256 257 346 347 356 357` [download]	[reply] [d/l]
Re: array combinations by BrowserUk (Patriarch) on Jun 26, 2008 at 13:46 UTC
My favorite module for this kind of thing is List::Comprehensions: `#! perl -slw use strict; use List::Comprehensions; my @a1 = qw(0 1 2 3 4); my @a2 = qw(0 1 2 3 4 5 6 7 8); my @a3 = qw(0 1); my @a4 = qw(0 1 2 3 4 5); comp1{ print "@_"; } \@a1, \@a2, \@a3, \@a4;` [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l]
Re: array combinations by dragonchild (Archbishop) on Jun 26, 2008 at 12:05 UTC
permutations - CPAN is your friend. My criteria for good software: Does it work? Can someone else come in, make a change, and be reasonably certain no bugs were introduced?	[reply]
Re: array combinations by linuxer (Curate) on Jul 01, 2008 at 18:41 UTC
What is "simple"? `use strict; use warnings; my @a = ( 1,2,3 ); my @b = ( 4,5 ); my @c = ( 6,7 ); my ( $x, $y, $z ); my @total = map { $x = $_; map { $y = $_; map { join '', $x, $y, $_ } + @c } @b } @a; { local $, = local $\ = $/; print @total; } __END__` [download] Result: `146 147 156 157 246 247 256 257 346 347 356 357` [download]	[reply] [d/l] [select]