PHP正则匹配字符串中的中文

<?php
$str = '这里是中文 this is English';
//把中文变成红色
echo preg_replace("/([x80-xff].)/","<font color=red>\1</font>",$str);
//把非中文变成红色
echo preg_replace("/([x20-x7f])/","<font color=red>\1</font>",$str);
?>

$str = "之二宽阔的甘家口东#标签1#标签2 #标签3。#标签4,都发$1234 ￥xc,cvm , ￥12,dflksjf如何#标签5.x #tag6.cvxcv“";
preg_match_all('/#([a-zA-Z0-9x7f-xff]+)/', $str, $mat);
print_r($mat);

preg_match("/[x{00a5}x{ffe5}](d+)/u", $str, $mat);
print_r($mat);

$str = "php编程";
if (preg_match("/^[x{4e00}-x{9fa5}]+$/u",$str)) {
print("该字符串全部是中文");
} else {
print("该字符串不全部是中文");
}

$str_arr = array(
"iameverysorry",
"快乐编程，快乐生活",
"php教程编程",
"1997年香港回归",
"英语学习abc",
"www.111cn.net"
);

$patt_ch = chr(0xa1) . "-" . chr(0xff);

foreach ($str_arr as $str)
{
    echo "字符串'$str' 是";
    if (preg_match("/^[$patt_ch]+$/", $str))
    {
        echo "<b>完全中文</b>";
        echo "<br>";
        echo "<br>";
    }
    else
    {
        echo "非完全中文";
        echo "<br>";
        echo "<br>";
    }
}