finding all combinations

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

Hello fellow monks, I wanted to ask the following:
Say you have 3 arrays, like

@array1=(1,2,3) , @array2(7,8)  and array3=(1,5,23,3);
[download]

Is there a way to find all combinations? I mean:

1-7-1, 1-7-5, 1-7-23, 1-7-3, 1-8-1, 1-8-5, 1-8-23, 1-8-3, 
2-7-1, 2-7-5, 2-7-23, 2-7-3, 2-8-1, 2-8-5, 2-8-23, 2-8-3,
3-7-1, 3-7-5, 3-7-23, 3-7-3, 3-8-1, 3-8-5, 3-8-23, 3-8-3
[download]

I tried using:

for ($i==0;$i<=$array1;$i++)
    {
        for ($j==0;$j<=$array2;$j++)
           {
               for ($k==0;$k<=$array3;$k++)
                   {
                       print $array1[$i], "\t", $array2[$j], "\t", $ar
+ray[$k], "\n";
                   }
           }
    }
[download]

but it only prints 1-7-1, 1-7-5, 1-7-23, 1-7-3 Could you give me any hint please?

Comment on finding all combinations Select or Download Code

Replies are listed 'Best First'.
Re: finding all combinations by Jim (Curate) on Jan 13, 2008 at 21:16 UTC
Start here: How do I find all possible combinations of array? Jim	[reply]
Re: finding all combinations by BrowserUk (Patriarch) on Jan 14, 2008 at 01:50 UTC
Just because it uses List::Comprehensions which I recently discovered and absolutely love: `use List::Comprehensions;; comp1 { print join '-', @_ } [1,2,3], [7,8], [1,5,23,3];; 1-7-1 1-7-5 1-7-23 1-7-3 1-8-1 1-8-5 1-8-23 1-8-3 2-7-1 2-7-5 2-7-23 2-7-3 2-8-1 2-8-5 2-8-23 2-8-3 3-7-1 3-7-5 3-7-23 3-7-3 3-8-1 3-8-5 3-8-23 3-8-3` [download] Or if you prefer: `comp1 { print join '-', reverse @_ } [1,5,23,3], [7,8], [1,2,3];; 1-7-1 2-7-1 3-7-1 1-8-1 2-8-1 3-8-1 1-7-5 2-7-5 3-7-5 1-8-5 2-8-5 3-8-5 1-7-23 2-7-23 3-7-23 1-8-23 2-8-23 3-8-23 1-7-3 2-7-3 3-7-3 1-8-3 2-8-3 3-8-3` [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] [select]
Re: finding all combinations by Anonymous Monk on Jan 13, 2008 at 21:50 UTC
Also, your loop comparison should be `$i <= $#array1` or `$i < @array1`, not `$i <= $array1`, which tries to compare `$i` to some (probably newly created) scalar `$array1`. Strong Suggestion: always `use warnings;` and `use strict;`, which would have alerted you to some, at least, of the errors noted. Another Suggestion: try using the Perl-style rather than the C-style for loop: `for my $i (@array1) { for my $j (@array2) { ... } }` [download]	[reply] [d/l] [select]
Re: finding all combinations by aquarium (Curate) on Jan 13, 2008 at 21:21 UTC
variable initialization/assignment is with "=" and not with "==", which is what you have inside your for loops. you're also missing a "3" in your print statement, which should end in $array3$k and not $array$k the hardest line to type correctly is: stty erase ^H	[reply]
Re: finding all combinations by lima1 (Curate) on Jan 13, 2008 at 23:20 UTC
`use strict; use warnings; my @array1 = (1,2,3); my @array2 = (7,8); my @array3 = (1,5,23,3); sub to_string { return '{' . join(q{,}, @_) . '}'; } print "$_ " while glob to_string(@array1) . q{-} . to_string(@array2) +. q{-} . to_string(@array3); __END__ 1-7-1 1-7-5 1-7-23 1-7-3 1-8-1 1-8-5 1-8-23 1-8-3 2-7-1 2-7-5 2-7-23 2 +-7-3 2-8-1 2-8-5 2-8-23 2-8-3 3-7-1 3-7-5 3-7-23 3-7-3 3-8-1 3-8-5 3- +8-23 3-8-3` [download] Update: Ah nice jwkrahn :) Did not know $".	[reply] [d/l]
Re^2: finding all combinations by jwkrahn (Abbot) on Jan 14, 2008 at 01:05 UTC
Or more succinctly: `my @array1 = (1,2,3); my @array2 = (7,8); my @array3 = (1,5,23,3); $" = ','; print "$_ " while glob "{@array1}-{@array2}-{@array3}";` [download]	[reply] [d/l]
Re: finding all combinations by roboticus (Chancellor) on Jan 14, 2008 at 03:00 UTC
Using Super Search, I found a couple threads you might check out: Finding all Combinations Notice the name of this thread! ;^) possible combinations in sequence ...roboticus	[reply]
Re: finding all combinations by brx (Pilgrim) on Jan 15, 2008 at 14:39 UTC
Using idea of ikegami ( N-Queens problem with a regex (again) ) With regex : `my @array1=(1,2,3); my @array2=(7,8); my @array3=(1,5,23,3); " @array1 , @array2 , @array3 " =~ / (\S+) .?,.? (\S+) .?,.? (\S+) (?{ push @res,"$1-$2-$3"; + })(?!)/; print join ', ',@res;` [download]	[reply] [d/l]
Re: finding all combinations by dokkeldepper (Friar) on Jan 18, 2008 at 12:53 UTC
ALgorithm::Combinatorics has everything you might ever combine.	[reply]


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