转载 php截取汉字

方法一

function dsubstr($string, $length, $suffix = '', $start = 0) {

if($start) {

$tmp = dsubstr($string, $start);

$string = substr($string, strlen($tmp));

}

$strlen = strlen($string);

if($strlen <= $length) return $string;

$string = str_replace(array('"', '<', '>'), array('"', '<', '>'), $string);

$length = $length - strlen($suffix);

$str = '';

if('UTF-8' == 'UTF-8') {

$n = $tn = $noc = 0;

while($n < $strlen) {

$t = ord($string{$n});

if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {

$tn = 1; $n++; $noc++;

} elseif(194 <= $t && $t <= 223) {

$tn = 2; $n += 2; $noc += 2;

} elseif(224 <= $t && $t <= 239) {

$tn = 3; $n += 3; $noc += 2;

} elseif(240 <= $t && $t <= 247) {

$tn = 4; $n += 4; $noc += 2;

} elseif(248 <= $t && $t <= 251) {

$tn = 5; $n += 5; $noc += 2;

} elseif($t == 252 || $t == 253) {

$tn = 6; $n += 6; $noc += 2;

} else {

$n++;

}

if($noc >= $length) break;

}

if($noc > $length) $n -= $tn;

$str = substr($string, 0, $n);

} else {

for($i = 0; $i < $length; $i++) {

$str .= ord($string{$i}) > 127 ? $string{$i}.$string{++$i} : $string{$i};

}

}

$str = str_replace(array('"', '<', '>'), array('"', '<', '>'), $str);

return $str == $string ? $str : $str.$suffix;

}

$content="该公司声明 还指e出，这一???航线并非永久性取消。与停止直飞北京的服务一样，公司将寻求美国运输部门的批准，暂停芝加哥与上海之间的航线，以便一旦条件改善，该直飞服务能重返市场。该公司表示，期待在2019年北京大兴机场投入使用时，能找到新的合作方式。";

echo dsubstr($content,27);

方法二

$text = "欢迎访问sina新浪播客";   
$value = substr($text, 0, 18);   
$value_length = strlen($value);      
$value_count = 0;      
for ($i = 0; $i < $value_length; $i++)      
{      
    if (ord($value{$i}) > 127)      
    {      
        $value_count++;      
    }      
}      
if ($value_count % 2 != 0)      
{      
    $value = substr($text, 0, $value_length - 1);    
}   
echo $value."
";   
?>