php 截取字串

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 1     /** 2      * 方法庫-截取字串-【該函數作者未知】 3      * @param string  $string 字串   4      * @param int     $length 字元長度 5      * @param string  $dot    截取後是否添加... 6      * @param string  $charset編碼 7      * @return string 8      */ 9     public function cutstr($string, $length, $dot = ‘ ...‘, $charset = ‘utf-8‘) {10         if (strlen($string) <= $length) {11             return $string;12         }13         $string = str_replace(array(‘&amp;‘, ‘&quot;‘, ‘&lt;‘, ‘&gt;‘), array(‘&‘, ‘"‘, ‘<‘, ‘>‘), $string);14         $strcut = ‘‘;15         if (strtolower($charset) == ‘utf-8‘) {16             $n = $tn = $noc = 0;17             while ($n < strlen($string)) {18                 $t = ord($string[$n]);                //ASCII?19                 if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {20                     $tn = 1; $n++; $noc++;21                 } elseif (194 <= $t && $t <= 223) {22                     $tn = 2; $n += 2; $noc += 2;23                 } elseif (224 <= $t && $t < 239) {24                     $tn = 3; $n += 3; $noc += 2;25                 } elseif (240 <= $t && $t <= 247) {26                     $tn = 4; $n += 4; $noc += 2;27                 } elseif (248 <= $t && $t <= 251) {28                     $tn = 5; $n += 5; $noc += 2;29                 } elseif ($t == 252 || $t == 253) {30                     $tn = 6; $n += 6; $noc += 2;31                 } else {32                     $n++;33                 }34                 if($noc >= $length) {35                     break;36                 }37             }38             if ($noc > $length) {39                 $n -= $tn;40             }41             $strcut = substr($string, 0, $n);42         } else {43             for ($i = 0; $i < $length; $i++) {44                 $strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];45             }46         }47         $strcut = str_replace(array(‘&‘, ‘"‘, ‘<‘, ‘>‘), array(‘&amp;‘, ‘&quot;‘, ‘&lt;‘, ‘&gt;‘), $strcut);48         return $strcut.$dot;49     }

 

php 截取字串