字符串操作 - 截取字符串长度代码段

标签：截取字符串长度   php   

提供一些项目中常用的字符串操作功能包括：截取字符串长度、输出转换、随机字符串、全角半角转换、字符集转换、邮箱格式验证、数字转文件大小.

<span style="font-family:SimSun;font-size:12px;">/**
 * 截取长度
 * @param unknown $str
 * @param number $start
 * @param unknown $length
 * @param string $charset
 * @param string $suffix
 * @return mixed|string
 */
public static function GetCsubStr($str,$start=0,$length,$charset="utf-8",$suffix=true){
	$charset=empty($charset)?'utf-8':$charset;
	$search=array('((\\\$[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)(\[[a-zA-Z0-9\-\.\[\]_\"\'\$\x7f-\xff]+\])*)','/<(\/?)(script|i?frame|style|html|body|title|link|meta|\?|\%)([^>]*?)>/isU',		// 去掉 javascript
	'/(<[^>]*)on[a-zA-Z] \s*=([^>]*>)/isU','/<[\/\!]*?[^<>]*?>/si',		// 去掉 HTML 标记
	'/([\r\n])[\s　]+/i',		// 去掉空白字符
	'/&(quot|#34);/i',		// 替换 HTML 实体
	'/&(amp|#38);/i','/&(lt|#60);/i','/&(gt|#62);/i','/&(nbsp|#160);/i','/&(iexcl|#161);/i','/&(cent|#162);/i','/&(pound|#163);/i','/&(copy|#169);/i','/&#(\d+);/e','/<\?/si','/\?>/si');
	$replace=array('([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)','<\\1\\2\\3>','\\1\\2',"","\r\n","","","","","","","","","","",'<?','?>');
	$str=preg_replace($search,$replace,$str);
	if(function_exists("mb_substr")){
		if(mb_strlen($str,$charset)<=$length){return $str;}
		$slice=mb_substr($str,$start,$length,$charset);
	}else{
		$re['utf-8']="/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";
		$re['gb2312']="/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";
		$re['gbk']="/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";
		$re['big5']="/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
		preg_match_all($re[$charset],$str,$match);
		if(!empty($match[0])&&count($match[0])<=$length){return $str;}
		$slice=join("",array_slice($match[0],$start,$length));
	}
	if($suffix){return $slice."…";}
	return $slice;
}</span>

preg_replace : 详细请查阅:PHP使用正则表达式查找替换字符串

代码段持续更新中...如果没有你需要的,可以留下你的评论,告诉你的需求.

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字符串操作 - 截取字符串长度代码段

标签：截取字符串长度   php   

原文地址：http://blog.csdn.net/websites/article/details/45246001