how to use recursion for nested foreach with each key in array

Question

I have an array

$array = array(
        0 => array('a1', 'a2'),
        1 => array('b4', 'b3', 'b5'),
        2=> array('c1', 'c3'),
        3=> array('d2' , 'd5', 'd6')
);

I want to process the array as the program below :

$data= array();
$tmp = array();
foreach($array[0] as $arr0){
    $tmp[0]= $arr0;
    foreach($array[1] as $arr1){
        $tmp[1]= $arr1;
        foreach($array[2] as $arr2){
            $tmp[2]= $arr2;
            foreach($array[3] as $arr3){
                $tmp[3]= $arr3;
                $data[]= $tmp;
            }
        }
    }
}

print_r($data);

So how to use recursion for this program ?.

You just want to print the array keys? your question isn't clear to me. — Pedro Lobito
– Pedro Lobito, Commented May 21, 2017 at 13:20
Learning recursion works best when you attempt to do it, fail and have a specific question instead of a request for someone to do it for you. :) — Jared Farrish
– Jared Farrish, Commented May 21, 2017 at 13:24
You posted only a 2-dimensional array, why would you iterate it 4 layers deep? — Kep
– Kep, Commented May 21, 2017 at 13:24
@ccKep - Look at it again, the first loop may be unnecessary or produce unexpected results. — Jared Farrish
– Jared Farrish, Commented May 21, 2017 at 13:25
Possible duplicate of All possible combinations in array - recursion? — Kep
– Kep, Commented May 21, 2017 at 13:29

LF-DevJourney · Accepted Answer · 2017-05-21 13:37:29Z

1

Try this, check the live demo.

$result = [];
$temp = [];
foreach($array as $arr)
{
    foreach($arr as $v)
    {
        if($result == [])
          $temp[] = [$v];
        else{
        foreach($result as $val)
        {
          $val [] = $v;
          $temp[] = $val;
        }
        }
    }
    $result = $temp;
    $temp = [];
}
print_r($result);

answered May 21, 2017 at 13:37

LF-DevJourney

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2 Comments

LF-DevJourney Over a year ago

it's just the order isuse. and my implementation is short of code than your order implementation. If it helps please accept it and upvote it

Rizier123 Over a year ago

While this code snippet may solve the question, including an explanation really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion. Please also try not to crowd your code with explanatory comments, this reduces the readability of both the code and the explanations!

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