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php正则函数2preg_match_all

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WBOYOriginal
2016-06-13 12:50:47737browse

php正则函数二preg_match_all

? ? ? ? 继续来说perl风格的正则函数preg_match_all。

? ? ? ? 函数原型:

?

<?php>
preg_match_all ($pattern, $subject, array &$matches = null, $flags = null, $offset = null)
<?>

?

? ? ? ? 参数:完全和preg_match一样。

?

? ? ? ? 函数功能:类似preg_match,在$subject字符串中匹配$pattern;跟preg_match不同的是,preg_match_all在匹配的第一个结果时不会停止搜索,一直搜索到$subject的结尾。

?

? ? ? ? 返回值:根据函数功能就会看出不仅仅返回0或1,preg_match_all会搜索整个$subject直至结尾,有几个匹配结果就返回几。看个有匹配结果的例子。

?

<?php>
	$url = 'http://www.sina.com.cn/abc/de/fg.php?fff.html?id=1';
	$matches = array();
	$pattern = '/(\.){1}[^.|?]+(\?){1}/i';
	$count = preg_match_all($pattern, $url, $matches);
	var_dump($count);
	var_dump($matches);
<?>

?输出

int 2

array (size=3)
  0 => 
    array (size=2)
      0 => string '.php?' (length=5)
      1 => string '.html?' (length=6)
  1 => 
    array (size=2)
      0 => string '.' (length=1)
      1 => string '.' (length=1)
  2 => 
    array (size=2)
      0 => string '?' (length=1)
      1 => string '?' (length=1)

?这个例子匹配到两个结果,分别是http://www.sina.com.cn/abc/de/fg.php?fff.html?id=1字符串中红色的两部分。大家会发现$matches中的元素也是数组类型,$matches[0]存放匹配的结果,$matches[1]存放子正则1匹配的结果,$matches[2]存放正则2匹配的结果。可能说的不太直观,看下图就明白了

?



黑色箭头是$pattern正则匹配,绿箭头是子正则匹配。

再看个未匹配成功的例子

<?php>
	$url = 'http://www.sina.com.cn/abc/de/fg.php?fff.html?id=1';
	$matches = array();
	$pattern = '/(\.){1}[^.|?]+(\?){2}/i';
	$count = preg_match_all($pattern, $url, $matches);
	var_dump($count);
	var_dump($matches);
<?>

?输出

int 0

array (size=3)
  0 => 
    array (size=0)
      empty
  1 => 
    array (size=0)
      empty
  2 => 
    array (size=0)
      empty

?

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