PHP正则表达式提取匹配标记包含特定单词的地方

Question

I have the following string:

<product><name>Tea</name><price>12</price></product>
<product><name>black coffee</name><price>23</price></product>
<product><name>cheap black-coffee</name><price>44</price></product>

I would like to grab all products where "coffee" or "coffee black" occurs.

I tried with the following code:

preg_match_all('/<product>(.*?)(black coffee|black-coffee)(.*?)<\/product>/is', $string, $result);

But that code merges two of the products in the array. As you can tell, I am not at all familiar with regex.

Answer 1

You need to use a negative lookahead assertion instead of .*? because .*? will also match <product> or </product> tags.

<product>((?:(?!<\/?product).)*?)(black coffee|black-coffee)((?:(?!<\/?product).)*?)<\/product>

DEMO

$re = "/<product>(?:(?:(?!<\\/?product).)*?)(?:black coffee|black-coffee)(?:(?:(?!<\\/?product).)*?)<\\/product>/is";
$str = "<product><name>Tea</name><price>12</price></product>\n<product><name>black coffee</name><price>23</price></product>\n<product><name>cheap black-coffee</name><price>44</price></product>";
preg_match_all($re, $str, $matches);
print_r($matches[0])