sortRegularIsNotRegular.php

$a = ["151", "1500"];
foreach($a as $item) { echo "Value `{$item}` is " . gettype($item) . PHP_EOL; }
//output: Value `151` is string
//output: Value `1500` is string
sort($a, SORT_REGULAR);
var_dump($a);
//output: array(2) {
//output:   [0] =>
//output:   string(3) "151"
//output:   [1] =>
//output:   string(4) "1500"
//output: }
sort($a, SORT_STRING);
var_dump($a);
//output: array(2) {
//output:   [0] =>
//output:   string(4) "1500"
//output:   [1] =>
//output:   string(3) "151"
//output: }