【www.gdgbn.com--php函数】

/mixed str_replace ( mixed $search , mixed $replace , mixed $subject [, int &$count ] )

个函数返回一个字符串或在出现问题的所有搜索给定的数组替换值替换。

如果你不喜欢需要更换的规则（如正则表达式），你应该始终使用此函数，而不是ereg_replace（）或preg_replace函数（）。
*/
// provides:
$bodytag = str_replace("%body%", "black", "");

// provides: hll wrld f php
$vowels = array("a", "e", "i", "o", "u", "a", "e", "i", "o", "u");
$onlyconsonants = str_replace($vowels, "", "hello world of php");

// provides: you should eat pizza, beer, and ice cream every day
$phrase  = "you should eat fruits, vegetables, and fiber every day.";
$healthy = array("fruits", "vegetables", "fiber");
$yummy   = array("pizza", "beer", "ice cream");

$newphrase = str_replace($healthy, $yummy, $phrase);

// provides: 2
$str = str_replace("ll", "", "good golly miss molly!", $count);
echo $count;

//利用str_replace函数指定替换次数

$array = array(
 array(0,1,2)
 );
function keywords( $str,$array )
{
 $count =0;
 foreach($array as $v){     
  if(strstr($str,strtolower($v[0]))!==false){       
   if( $count <=3 ){
    $tos = strtolower($v[0]);
    $str=preg_replace("/$tos/","".$v[2]."",$str,1);
    $count++;
    continue;
   }
  }    
 }
 return $str;  
}

?>

本文来源：http://www.gdgbn.com/jiaocheng/27356/