php字串截取的代碼學習

//截取utf8字串 function utf8Substr($str, $from, $len) { return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'. '((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s', '$1',$str); } ?> 複製代碼 2、UTF-8、GB2312都支援的漢字截取函數 function cut_str($string, $sublen, $start = 0, $code = 'UTF-8') { if($code == 'UTF-8') { $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/"; preg_match_all($pa, $string, $t_string); if(count($t_string[0])- $start > $sublen)return join('', array_slice($t_string[0], $start, $sublen))."..."; return join('', array_slice($t_string[0], $start, $sublen)); } else { $start = $start*2; $sublen = $sublen*2; $strlen = strlen($string); $tmpstr = ''; for($i=0;$i<$strlen;$i++) { if($i>=$start && $i<($start+$sublen)) { if(ord(substr($string, $i, 1))>129) { $tmpstr.= substr($string, $i, 2); } else { $tmpstr.= substr($string, $i, 1); } } if(ord(substr($string, $i, 1))>129)$i++; } if(strlen($tmpstr)<$strlen )$tmpstr.= "..."; return $tmpstr; } } $str = "abcd需要截取的字串"; echo cut_str($str, 8, 0, 'gb2312'); ?> 複製代碼 3、BugFree 的字元截取函數 function sysSubStr($String,$Length,$Append = false) { if (strlen($String)<= $Length ) { return $String; } else { $I = 0; while ($I < $Length) { $StringTMP = substr($String,$I,1); if (ord($StringTMP)>=224 ) { $StringTMP = substr($String,$I,3); $I = $I + 3; } elseif(ord($StringTMP)>=192 ) { $StringTMP = substr($String,$I,2); $I = $I + 2; } else { $I = $I + 1; } $StringLast[]= $StringTMP; } $StringLast = implode("",$StringLast); if($Append) { $StringLast .= "..."; } return $StringLast; } } $String = "CodeBit.cn -- 簡單、精彩、通用"; $Length = "18"; $Append = false; echo sysSubStr($String,$Length,$Append); ?> 複製代碼

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