批量替换preg_replace，写文件

$patterns = array();
$patterns[0] = '/</';

$patterns[1] = '/>/';

$patterns[2] = '/ /';
$replacements = array();
$replacements[2] = '';$replacements[1] = '';$replacements[0] = '';

$byte = preg_replace($patterns,$replacements,$str1['pic']);
$byte = pack("H*",$byte); //16进制转换成二进制
$filename = time().mt_rand().".png";
$a = file_put_contents( "Public/Home/images/user/".$filename,$byte);