php字串截取方法大全 php截取字串四個例子

//截取中文字串 function mysubstr($str, $start, $len) { $tmpstr = ""; $strlen = $start + $len; for($i = 0; $i < $strlen; $i++) { if(ord(substr($str, $i, 1)) --> 0xa0) { $tmpstr .= substr($str, $i, 2); $i++; } else $tmpstr .= substr($str, $i, 1); } return $tmpstr; } ?> 複製代碼 2、截取utf8編碼的多位元組字串 //截取utf8字串 function utf8Substr($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 3、UTF-8、GB2312都支援的漢字截取函數 /* Utf-8、gb2312都支援的漢字截取函數 cut_str(字串, 截取長度, 開始長度, 編碼); 編碼預設為 utf-8 開始長度預設為 0 */ 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 4、BugFree 的字元截取函數 /** * @package BugFree * @version $Id: FunctionsMain.inc.php,v 1.32 2005/09/24 11:38:37 wwccss Exp $ * * * Return part of a string(Enhance the function substr()) * * @author Chunsheng Wang * @param string $String the string to cut. * @param int $Length the length of returned string. * @param booble $Append whether append "...": false|true * @return string the cutted string. */ function sysSubStr($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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