is_numeric_array

is_numeric_array.php

<?php

$a1 = array('x', 'a' => 'b', 'c', 'd', 'e');
print_r($a1);

var_dump(is_numeric_array($a1)); // false


$a2 = array('a', 'b', 'c', 'd', 'e');
print_r($a2);

var_dump(is_numeric_array($a2)); // true


$a3 = array_fill(1, 6, 0) + array(0);
print_r($a3);

var_dump(is_numeric_array($a3)); // false, because keys start at 1


$a4 = $a2;
unset($a4[2]);
print_r($a4);

var_dump(is_numeric_array($a4)); // false, because missing key in the middle


function is_numeric_array($arr) {
  return $arr === array() || range(0, count($arr)-1) === array_keys($arr);
}