You want to find the nth word match instead of the first one.
Use preg_match_all() to pull all the matches into an array; then pick out the specific matches in which you’re interested, as shown in Example 23-4.
Example 23-4. Finding the nth match
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$todo = "1. Get Dressed 2. Eat Jelly 3. Squash every week into a day"; preg_match_all("/\d\. ([^\d]+)/", $todo, $matches); print "The second item on the todo list is: "; // $matches[1] is an array of each substring captured by ([^\d]+) print $matches[1][1] . "\n"; print "The entire todo list is: "; foreach($matches[1] as $match) { print "$match\n"; } |
Because the preg_match() function stops after it finds one match, you need to use preg_match_all() instead if you’re looking for additional matches.
The preg_match_all() function returns the number of full pattern matches it finds. If it finds no matches, it returns 0. If it encounters an error, such as a syntax problem in the pattern, it returns false.
The third argument to preg_match_all() is populated with an array holding information about the various substrings that the pattern has matched.
The first element holds an array of matches of the complete pattern. For Example 23-4, this means that $match
es[0] holds the parts of $todo that match /\d\. ([^\d]+)/: 1.
Get Dressed, 2. Eat Jelly, and 3. Squash every week into a day.
Subsequent elements of the $matches array hold arrays of text matched by each parenthesized subpattern.
The pattern in Example 23-4 has just one subpattern ([^\d\]+). So $matches[1] is an array of strings that match that subpattern: Get Dressed, Eat Jelly, and Squash every week into a day.
If there were a second subpattern, the substrings that it matched would be in $match es[2], a third subpattern’s matches would be in $matches[3], and so on.
Instead of returning an array divided into full matches and then submatches, preg_match_all() can return an array divided by matches, with each submatch inside.
To trigger this, pass PREG_SET_ORDER in as the fourth argument.
This is particularly useful when you’ve got multiple captured subpatterns and you want to iterate through
the subpattern groups one group at a time, as shown in Example 23-5.
Example 23-5. Grouping captured subpatterns
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$todo = " first=Get Dressed next=Eat Jelly last=Squash every week into a day "; preg_match_all("/([a-zA-Z]+)=(.*)/", $todo, $matches, PREG_SET_ORDER); foreach ($matches as $match) { print "The {$match[1]} action is {$match[2]}\n"; } |
Example 23-5 prints:
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The first action is Get Dressed The next action is Eat Jelly The last action is Squash every week into a day |
With PREG_SET_ORDER, each value of $match in the foreach loop contains all the subpatterns: $match[0] is the entire matched string, $match[1] the bit before the =, and $match[2] the bit after the =.
