How to find all possible order with array item

Question

Here is an array.

$item = array('A', 'B', 'C', 'D');

I want to list all possible orders in this array like:

A
A,B
A,B,C
A,B,C,D
A,C
A,C,D
A,C,B
...
B,A
B,A,C
....

How can I do that?

I think you should try yourself... try googling recursivity and permutation — de3, Jan 16 '12 at 09:30
There is nothing special about `php` in this problem. Its a general algorithm. You just need to know the algorithm. You can say "in php" IMO if you show us what codes you have written till now. — footy, Jan 16 '12 at 09:31
First result on Google: http://www.hashbangcode.com/blog/getting-all-permutations-array-php-74.html — Quasdunk, Jan 16 '12 at 09:33
possible duplicate of [Permutations - all possible sets of numbers](http://stackoverflow.com/questions/5506888/permutations-all-possible-sets-of-numbers) — zaf, Jan 16 '12 at 09:45

score 2 · Accepted Answer · edited May 23 '17 at 11:48

2

The permutations you want to know can be accomplished through this algorithm and applying in a loop for the subsets.

Initialize the first permutation with <1 <2 ...
while there exists a mobile integer

find the largest mobile integer k

swap k and the adjacent integer it is looking at

reverse the direction of all integers larger than k

Refer to this question for more info

edited May 23 '17 at 11:48

Community

1
1

answered Jan 16 '12 at 09:35

footy

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score 1 · Answer 2 · answered Jan 16 '12 at 09:34

You can use this recursive function:

function recursive_permutations($items,$perms = array( ))
{
 static $list;
 if (empty($items)) {
  $list[] = join(',', $perms);
 } else {
  for ($i = count($items)-1;$i>=0;--$i) {
   $newitems = $items;
   $newperms = $perms;
   list($foo) = array_splice($newitems, $i, 1);
   array_unshift($newperms, $foo);
   recursive_permutations($newitems, $newperms);
  };
  return $list;
 };
}
$perms = recursive_permutations(array('A', 'B', 'C', 'D'));
echo '<pre>' . print_r($perms, true) . '</pre>';

How to find all possible order with array item

2 Answers2