Question

Is there a function which I could give an array, which would return true if the provided function returned true for all of them?

theFunction(array(1,2,3) , 'is_numeric') //true
theFunction(array(1,"b",3) , 'is_numeric') //false

Answer 1

No, but you can use array_reduce:

array_reduce(array(1,2,3),
    function ($a, $v) { return $a && is_numeric($v); }, true);

You can of course build your own higher-order function:

function for_all(array $arr, $func) {
    return array_reduce($arr,
        function ($a, $v) use ($func) {
            return $a && call_user_func($func, $v);
        }, true);
}

var_dump(
    for_all(array(1,2,3), 'is_numeric')
); //true