Dynamic array keys

Question

I have a string like this:

$string = \'one/two/three/four\';

which I turn it into a array:

$keys = explode(\'/\', $string);

Answer 1

it's corny but:

function setValueByArrayKeys($array_keys, &$multi, $value) {
     $m = &$multi
     foreach ($array_keys as $k){
         $m = &$m[$k];
     }
     $m = $value;
}

Answer 2

$string = 'one/two/three/four';
$keys = explode('/', $string);
$arr = array(); // some big array with lots of dimensions
$ref = &$arr;

while ($key = array_shift($keys)) {
    $ref = &$ref[$key];
}

$ref = 'value';

What this is doing:

• Using a variable, $ref, to keep track of a reference to the current dimension of $arr.
• Looping through $keys one at a time, referencing the $key element of the current reference.
• Setting the value to the final reference.

Answer 3

This is kind of non-trivial because you want to nest, but it should go something like:

function insert_using_keys($arr, $keys, $value){
    // we're modifying a copy of $arr, but here
    // we obtain a reference to it. we move the
    // reference in order to set the values.
    $a = &$arr;

    while( count($keys) > 0 ){
        // get next first key
        $k = array_shift($keys);

        // if $a isn't an array already, make it one
        if(!is_array($a)){
            $a = array();
        }

        // move the reference deeper
        $a = &$a[$k];
    }
    $a = $value;

    // return a copy of $arr with the value set
    return $arr;
}

Answer 4

    $arr['one']['two']['three']['four'] = 'value';

    $string = 'one/two/three/four';
    $ExpCheck = explode("/", $string);
    $CheckVal = $arr;
    foreach($ExpCheck AS $eVal){
        $CheckVal = $CheckVal[$eVal]??false;
        if (!$CheckVal)
            break;
    }
    if ($CheckVal) {
        $val =$CheckVal;
    }

this will give u your value in array.

Answer 5

You'll need to first make sure the key's exist, then assign the value. Something like this should work (untested):

function addValueByNestedKey(&$array, $keys, $value) {
    $branch = &$array;
    $key = array_shift($keys);
    // add keys, maintaining reference to latest branch:
    while(count($keys)) {
        $key = array_pop($keys);
        if(!array_key_exists($key, $branch) {
            $branch[$key] = array();
        }
        $branch = &$branch[$key];
    }
    $branch[$key] = $value;
}

// usage:
$arr = array();
$keys = explode('/', 'one/two/three/four');

addValueByNestedKey($arr, $keys, 'value');