Extracting matches from php regex

Question

In perl regex we can extract the matched variables, ex below.

   # extract hours, minutes, seconds
   $time =~ /(\d\d):(\d\d):(\d\d)/; # match hh:mm:ss format
   $hours = $1;
   $minutes = $2;
   $seconds = $3;

How to do this in php?

$subject = "E:[email protected] I:100955";
$pattern = "/^E:/";
if (preg_match($pattern, $subject)) {
    echo "Yes, A Match";
}

How to extract the email from there? (We can explode it and get it...but would like a method to get it directly through regex)?

Answer 1

Use the matchs parameter of the preg_match function as follows:

matches:
If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.

Answer 2

Check the php manual

int preg_match ( string $pattern , string $subject [, array &$matches [, int $flags [, int $offset ]]] )

If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.

$subject = "E:[email protected] I:100955";
$pattern = "/^E:(?<contact>\w+) I:(?<id>\d+)$/";
if (preg_match($pattern, $subject,$matches)) {
    print_r($matches);
}

Answer 3

Try using the named subpattern syntax of preg_match:

<?php

$str = 'foobar: 2008';

// Works in PHP 5.2.2 and later.
preg_match('/(?<name>\w+): (?<digit>\d+)/', $str, $matches);

// Before PHP 5.2.2, use this:
// preg_match('/(?P<name>\w+): (?P<digit>\d+)/', $str, $matches);

print_r($matches);

?>

Output:

 Array (
     [0] => foobar: 2008
     [name] => foobar
     [1] => foobar
     [digit] => 2008
     [2] => 2008 )

Answer 4

You can just modify your current regexp to capture everything after the colon up to the first space:

$subject = "E:[email protected] I:100955";
$pattern = "/^E:([^ ]+)/";
if (preg_match($pattern, $subject, $m)) {
    echo "Yes, A Match";
}
$email = $m[1];

In case you're not familiar with regexp, [^ ]+ means "any character but a space" and it doesn't require a space to be present to work. If for any reason the input changes to "E:[email protected]" without the " I:12345" bit, it will still work.