- print_r: documentation ( source)
- array_filter: documentation ( source)
<?php
$source=array(array("DOS"=>"Apr 3 2013","flag"=>"hit"),array("DOS"=>"Apr 4 2013","flag"=>"no hit"),array("DOS"=>"Apr 3 2013","flag"=>"hit"));
$cond="Apr 3 2013";
$result=array_filter($source,function($v)use($cond){
return $v["DOS"]==$cond;
});
print_r($result);