PHP Find All (somewhat) Unique Combinations of an Array

Question

I\'ve been looking at PHP array permutation / combination questions all day.. and still can\'t figure it out :/

If I have an array like:

20 //key bei         


        

Answer 1

Why not just use binary? At least then its simple and very easy to understand what each line of code does like this? Here's a function i wrote for myself in a project which i think is pretty neat!

function search_get_combos($array){
$bits = count($array); //bits of binary number equal to number of words in query;
//Convert decimal number to binary with set number of bits, and split into array
$dec = 1;
$binary = str_split(str_pad(decbin($dec), $bits, '0', STR_PAD_LEFT));
while($dec < pow(2, $bits)) {
    //Each 'word' is linked to a bit of the binary number.
    //Whenever the bit is '1' its added to the current term.
    $curterm = "";
    $i = 0;
    while($i < ($bits)){
        if($binary[$i] == 1) {
            $curterm[] = $array[$i]." ";
        }
        $i++;
    }
    $terms[] = $curterm;
    //Count up by 1
    $dec++;
    $binary = str_split(str_pad(decbin($dec), $bits, '0', STR_PAD_LEFT));
}
return $terms;
} 

For your example, this outputs:

Array
(
    [0] => Array
        (
            [0] => 24 
        )
    [1] => Array
        (
            [0] => 22 
        )
    [2] => Array
        (
            [0] => 22 
            [1] => 24 
        )
    [3] => Array
        (
            [0] => 20 
        )
    [4] => Array
        (
            [0] => 20 
            [1] => 24 
        )
    [5] => Array
        (
            [0] => 20 
            [1] => 22 
        )
    [6] => Array
        (
            [0] => 20 
            [1] => 22 
            [2] => 24 
        )
    [7] => Array
        (
            [0] => 20 
        )
    [8] => Array
        (
            [0] => 20 
            [1] => 24 
        )
    [9] => Array
        (
            [0] => 20 
            [1] => 22 
        )
    [10] => Array
        (
            [0] => 20 
            [1] => 22 
            [2] => 24 
        )
    [11] => Array
        (
            [0] => 20 
            [1] => 20 
        )
    [12] => Array
        (
            [0] => 20 
            [1] => 20 
            [2] => 24 
        )
    [13] => Array
        (
            [0] => 20 
            [1] => 20 
            [2] => 22 
        )
    [14] => Array
        (
            [0] => 20 
            [1] => 20 
            [2] => 22 
            [3] => 24 
        )
)