获取php中许多数组的所有可能迭代

Question

I have few arrays for example:

array(
    'color' => array('red', 'blue', ...);
    'size' => array('small', 'big', ...);
    'temp' => array('hot', 'cold', ...);
     ...
)

Is there a function so I can get all possible iterations of these arrays ? (and more arrays and values if needed). For example result should be:

array(
    0 => array('color'=> 'red', 'size'=>'small', 'temp'=>'hot')
    1 =>  array('color'=> 'red', 'size'=>'small', 'temp'=>'cold')
    2 =>  array('color'=> 'red', 'size'=>'big', 'temp'=>'hot')
    3 =>  array('color'=> 'red', 'size'=>'big', 'temp'=>'cold')
)

... and so on.

Answer 1

Use a recursive approach:

function generateCombinations($array, $start = 0) {
    $size = count($array);
    if ($size == $start) {
        return array('');
    }
    $result = array();
    foreach ($array[$start] as $val) {
        foreach (generateCombinations($array, $start + 1, $size) as $last) {
            $result[] = $val . ' ' . $last;
        }
    }
    return $result;
}

Usage:

$array = array(
    array('red', 'blue'), 
    array('small', 'big'),
    array('hot', 'cold')
);

$result = generateCombinations($array);
print_r($result);

Output:

Array
(
    [0] => red small hot 
    [1] => red small cold 
    [2] => red big hot 
    [3] => red big cold 
    [4] => blue small hot 
    [5] => blue small cold 
    [6] => blue big hot 
    [7] => blue big cold 
)

Online Demo