正则表达式,匹配查找函数(preg_match_all)flags参数对比
格式:
int preg_match_all ( string pattern, string subject, array matches [, int flags] )
参数 flags 选项有以下3个:
PREG_PATTERN_ORDER //是默认参数 PREG_SET_ORDER PREG_OFFSET_CAPTURE
我们用例子来看看 PREG_PATTERN_ORDER 和 PREG_SET_ORDER 的区别。(须查看源代码)
<?php $str = '<a href="http://www.baidu.com/">百度</a>, <a href="http://www.google.com/">谷歌</a>, <a href="http://www.caiguai.net/">怪手论坛</a>'; preg_match_all('/<a href="(.*?)">(.*?)<\/a>/', $str, $matches_pattern, PREG_PATTERN_ORDER); preg_match_all('/<a href="(.*?)">(.*?)<\/a>/', $str, $matches_set, PREG_SET_ORDER); echo "<pre>"; print_r($matches_pattern); echo "<p>"; print_r($matches_set);
$matches_pattern 返回的数据为:
Array ( [0] => Array ( [0] => <a href="http://www.baidu.com/">百度</a> [1] => <a href="http://www.google.com/">谷歌</a> [2] => <a href="http://www.caiguai.net/">怪手论坛</a> ) [1] => Array ( [0] => http://www.baidu.com/ [1] => http://www.google.com/ [2] => http://www.caiguai.net/ ) [2] => Array ( [0] => 百度 [1] => 谷歌 [2] => 怪手论坛 ) )
$matches_set 返回的数据为:
Array ( [0] => Array ( [0] => <a href="http://www.baidu.com/">百度</a> [1] => http://www.baidu.com/ [2] => 百度 ) [1] => Array ( [0] => <a href="http://www.google.com/">谷歌</a> [1] => http://www.google.com/ [2] => 谷歌 ) [2] => Array ( [0] => <a href="http://www.caiguai.net/">怪手论坛</a> [1] => http://www.caiguai.net/ [2] => 怪手论坛 ) )
而根据我之前阅读别人代码,就一直认为应该这么来组合结果:
foreach ($matches_pattern[0] as $tid=>$val) { echo '链接:'.$matches_pattern[1][$tid]; echo '网址:'.$matches_pattern[2][$tid]; echo "\r\n"; } /** * 返回结果为: * 链接:http://www.baidu.com/网址:百度 链接:http://www.google.com/网址:谷歌 链接:http://www.caiguai.net/网址:怪手论坛 */
而PREG_SET_ORDER,就在于重新组合的数据,使得数组数据可以更方便的利用:
foreach ($matches_set as $v) { echo '链接:'.$v[1]; echo '网址:'.$v[2]; echo "\r\n"; } /** * 返回结果为: * 链接:http://www.baidu.com/网址:百度 链接:http://www.google.com/网址:谷歌 链接:http://www.caiguai.net/网址:怪手论坛 */
posted on 2017-11-17 02:44 zhuyongzhe 阅读(431) 评论(0) 编辑 收藏 举报