php 문법 관련 간단한 질문요

<?php
$tmp_array = array();
#for($i = 0; $i < count($id_array); $i++)
for($i = 0; $i < 10; $i++)
{
    $tmp_value = (string)$i;
 
    array_push($tmp_array, $tmp_value);
}
 
var_dump ($tmp_array);
?>

array(10) {
  [0]=>
  string(1) "0"
  [1]=>
  string(1) "1"
  [2]=>
  string(1) "2"
  [3]=>
  string(1) "3"
  [4]=>
  string(1) "4"
  [5]=>
  string(1) "5"
  [6]=>
  string(1) "6"
  [7]=>
  string(1) "7"
  [8]=>
  string(1) "8"
  [9]=>
  string(1) "9"
}