PHP convert nested array to single array while concatenating keys?

Question

Here is an example array:

 $foo = array(
           \'employer\' => array(
                    \'name\' => \'Foobar Inc\',
                    \'phone\         


        

Answer 1

A solution whith only array_* php functions + recursive :

$array = array(
    "level1"=>"value",
    "level2" => ["level11" => "value", "level21" => "value"],
    "level3" => ["level2" => ["level1" => "value"]],
    "level4" => ["level3" => ["level2" => ["level1" => "value"]]],
    "level5" => ["level4" => ["level3" => ["level2" => ["level1" => "value"]]]],
);
 
//flatten array with combined keys
function arrayFlat($array) {
    $result = [];
    array_walk($array, function($v, $pk)use(&$result){
        if(is_array($v)) {
            $result += arrayFlat(array_combine(
                array_map(function($k) use($pk){ return $pk . '_' .$k; }, array_keys($v)),
                $v
            ));
        } else {
            $result[$pk] = $v;
        }
    });
    return $result;
}

print_r(arrayFlat($array));

Output :

Array
(
    [level1] => value
    [level2_level11] => value
    [level2_level21] => value
    [level3_level2_level1] => value
    [level4_level3_level2_level1] => value
    [level5_level4_level3_level2_level1] => value
)