--TEST-- Using different sorts of numerical strings as an array offset --FILE-- <?php $arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]; var_dump($arr["7"]); var_dump($arr["7.5"]); var_dump($arr[" 7"]); var_dump($arr[" 7.5"]); var_dump($arr[" 7 "]); var_dump($arr[" 7.5 "]); var_dump($arr["7 "]); var_dump($arr["7.5 "]); var_dump($arr["7str"]); var_dump($arr["7.5str"]); var_dump($arr[" 7str"]); var_dump($arr[" 7.5str"]); var_dump($arr[" 7 str"]); var_dump($arr[" 7.5 str"]); var_dump($arr["7 str"]); var_dump($arr["7.5 str"]); var_dump($arr["0xA"]); var_dump($arr["0b10"]); var_dump($arr["07"]); echo "Done\n"; ?> --EXPECTF-- int(7) Warning: Undefined array key "7.5" in %s on line %d NULL Warning: Undefined array key " 7" in %s on line %d NULL Warning: Undefined array key " 7.5" in %s on line %d NULL Warning: Undefined array key " 7 " in %s on line %d NULL Warning: Undefined array key " 7.5 " in %s on line %d NULL Warning: Undefined array key "7 " in %s on line %d NULL Warning: Undefined array key "7.5 " in %s on line %d NULL Warning: Undefined array key "7str" in %s on line %d NULL Warning: Undefined array key "7.5str" in %s on line %d NULL Warning: Undefined array key " 7str" in %s on line %d NULL Warning: Undefined array key " 7.5str" in %s on line %d NULL Warning: Undefined array key " 7 str" in %s on line %d NULL Warning: Undefined array key " 7.5 str" in %s on line %d NULL Warning: Undefined array key "7 str" in %s on line %d NULL Warning: Undefined array key "7.5 str" in %s on line %d NULL Warning: Undefined array key "0xA" in %s on line %d NULL Warning: Undefined array key "0b10" in %s on line %d NULL Warning: Undefined array key "07" in %s on line %d NULL Done