<?php
 //数组使用标准比较运算符这样比较的
 function standard_array_compare($op1,$op2)
 {
 if(count($op1) < count($op2)) {
  return -1; //$op1 < $op2
 } else if(count($op1) > count($op1)) {
  return 1; //$op1 > op2
 }
 foreach ($op1 as $key => $val) {
  if(!array_key_exists($key,$op2)) {
  return null;
  } else if ($val < $op2[$key]) {
  return -1;
  } else if ($val > $op2[$key]) {
  return 1;
  }
 }
 return 0;
 }
 $arr1 = array(1,2,3,4,5);
 $arr2 = array(1,2,3,4,5);
 $arr3 = array(2,3,4,5,6);
 $arr4 = array(0,1,2,3,4);
 var_dump(standard_array_compare($arr1,$arr2));
 echo "<br/>";
 var_dump(standard_array_compare($arr1,$arr3));
 echo "<br/>";
 var_dump(standard_array_compare($arr1,$arr4));
?>