22.7.1. ProblemYou've used parentheses for grouping in a pattern, but you don't want the text that matches what's in the parentheses to show up in your array of captured matches. 22.7.2. SolutionPut ?: just after the opening parenthesis, as in Example 22-13. Preventing text capture
In Example 22-13, $bothMatches contains the values of the rel and the HRef attributes. $linkMatches, however, just contains the values of the href attributes. The code prints: $bothMatches is: array(3) { [0]=> array(2) { [0]=> string(49) "rel="prev" href="http://www.example.com/prev.xml"" [1]=> string(49) "rel="next" href="http://www.example.com/next.xml"" } [1]=> array(2) { [0]=> string(4) "prev" [1]=> string(4) "next" } [2]=> array(2) { [0]=> string(31) "http://www.example.com/prev.xml" [1]=> string(31) "http://www.example.com/next.xml" } } $linkMatches is: array(2) { [0]=> array(2) { [0]=> string(49) "rel="prev" href="http://www.example.com/prev.xml"" [1]=> string(49) "rel="next" href="http://www.example.com/next.xml"" } [1]=> array(2) { [0]=> string(31) "http://www.example.com/prev.xml" [1]=> string(31) "http://www.example.com/next.xml" } } 22.7.3. DiscussionPreventing capturing is particularly useful when a subpattern is optional. Since it might not show up in the array of captured text, an optional subpattern can change the number of pieces of captured text. This makes it hard to reference a particular matched piece of text at a given index. Making optional subpatterns non-capturing prevents this problem. Example 22-14 illustrates this distinction. A non-capturing optional subpattern
22.7.4. See AlsoThe PCRE Pattern Syntax documentation at http://php.net/reference.pcre.pattern.syntax. |