如何在PHP中比较数组值？

Question

I need to compare the array values with each other.These values are unique IDs. So, have to check whether ID values are repeated.

<?php
 $id=array("firstid2012","secondid2014","thirddid2010","fourthid2014");
 $idcount=count($id);
 for($i=0;$i<$idcount;$i++){
 //how to compare?? 
 }  
 ?>

If repeated id is true, then i have to change the value of that array value.So I need to know which array value is repeated also.

Answer 1

if (count($idvalues) == count(array_unique($idvalues))){
  //ALL VALUES ARE DISTINCTS
}
else {
  //THERE ARE DUPLICATED VALUES
  $duplicated=array();
  $visited=array();
  foreach($idvalues as $value){
      if (in_array($value,$visited)){
         $duplicated[]=$value;
      }
      $visited[]=$value;
  }
  $duplicated=array_uniq($duplicated);
}