php删除字符串中的所有空格

php删除字符串中的所有空格
其实是对trim函数的扩展
trim只能删除字符串两边的空格

function trimall($str)//删除空格
{
    $qian=array(" ","　","\t","\n","\r");
         $hou=array("","","","","");
    return str_replace($qian,$hou,$str);    
}