PHP针对中英文混合字符串长度判断及截取方法示例

/** *  * 中英混合字符串长度判断  * @param unknown_type $str * @param unknown_type $charset */function strLength($str, $charset = 'utf-8') {  if ($charset == 'utf-8')    $str = iconv ( 'utf-8', 'gb2312', $str );  $num = strlen ( $str );  $cnNum = 0;  for($i = 0; $i < $num; $i ++) {    if (ord ( substr ( $str, $i + 1, 1 ) ) > 127) {      $cnNum ++;      $i ++;    }  }  $enNum = $num - ($cnNum * 2);  $number = ($enNum / 2) + $cnNum;  return ceil ( $number );}

/** *  * 中英混合的字符串截取 * @param unknown_type $sourcestr * @param unknown_type $cutlength */function cut_str($sourcestr, $cutlength) {  $returnstr = '';  $i = 0;  $n = 0;  $str_length = strlen ( $sourcestr ); //字符串的字节数   while ( ($n < $cutlength) and ($i <= $str_length) ) {    $temp_str = substr ( $sourcestr, $i, 1 );    $ascnum = Ord ( $temp_str ); //得到字符串中第$i位字符的ascii码     if ($ascnum >= 224) //如果ASCII位高与224，    {      $returnstr = $returnstr . substr ( $sourcestr, $i, 3 ); //根据UTF-8编码规范，将3个连续的字符计为单个字符         $i = $i + 3; //实际Byte计为3      $n ++; //字串长度计1    } elseif ($ascnum >= 192) //如果ASCII位高与192，    {      $returnstr = $returnstr . substr ( $sourcestr, $i, 2 ); //根据UTF-8编码规范，将2个连续的字符计为单个字符       $i = $i + 2; //实际Byte计为2      $n ++; //字串长度计1    } elseif ($ascnum >= 65 && $ascnum <= 90) //如果是大写字母，    {      $returnstr = $returnstr . substr ( $sourcestr, $i, 1 );      $i = $i + 1; //实际的Byte数仍计1个      $n ++; //但考虑整体美观，大写字母计成一个高位字符    } else //其他情况下，包括小写字母和半角标点符号，    {      $returnstr = $returnstr . substr ( $sourcestr, $i, 1 );      $i = $i + 1; //实际的Byte数计1个      $n = $n + 0.5; //小写字母和半角标点等与半个高位字符宽...    }  }  if ($str_length > $cutlength) {    $returnstr = $returnstr . "..."; //超过长度时在尾处加上省略号  }  return $returnstr;}