PHP 替换函数

function trimall($str)//删除空格

{    

$qian=array(" "," ","\t","\n","\r");$hou=array("","","","","");

return str_replace($qian,$hou,$str);

}

上面自定义函数是将指定内容替换，其中所使用的系统函数为：str_replace