(PHP Extension) Regular Expression with Capture Groups

See more Regular Expressions Examples

Note: Chilkat uses PCRE2. See PCRE2 Regular Expressions
Also see: PCRE2 Performance

Demonstrates the following PCRE2 regular expression:

See the sample code below.

Name:\s+(\w+)\s+(\w+),\s+Email:\s+(\S+)

And apply it to this string:

Name: John Smith, Email: john.smith@example.com

Regex Components Explained

Matches for Your Example String

String:

"Name: John Smith, Email: john.smith@example.com"

Regex Match Groups:

Notes on Character Classes

• \w matches [a-zA-Z0-9_] — so it doesn’t include punctuation like a period.
• \S matches any non-whitespace character, so it’s good for capturing an email.

Note: This example requires Chilkat v11.1.0 or greater.

For more information, see https://www.chilkatsoft.com/chilkat_pcre2.asp

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<?php

include("chilkat.php");

$success = false;

$subject = 'Name: John Smith, Email: john.smith@example.com';
$pattern = 'Name:\\s+(\\w+)\\s+(\\w+),\\s+Email:\\s+(\\S+)';

$sb = new CkStringBuilder();
$sb->Append($subject);

$json = new CkJsonObject();
$json->put_EmitCompact(false);

$timeoutMs = 2000;
$numMatches = $sb->RegexMatch($pattern,$json,$timeoutMs);
if ($numMatches < 0) {
    // Probably an error in the regular expression.
    // Suggestion: Use AI to help create and/or diagnose regular expressions.
    print $sb->lastErrorText() . "\n";
    exit;
}

// Examine the matches:
print $json->emit() . "\n";

// This is the JSON with the match information.
// See the JSON parsing code below to get the matched capture group values.

// Important:  Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

// {
//   "match": [
//     {
//       "group": [
//         {
//           "cap": "Name: John Smith, Email: john.smith@example.com",
//           "idx": 0,
//           "len": 47
//         },
//         {
//           "cap": "John",
//           "idx": 6,
//           "len": 4
//         },
//         {
//           "cap": "Smith",
//           "idx": 11,
//           "len": 5
//         },
//         {
//           "cap": "john.smith@example.com",
//           "idx": 25,
//           "len": 22
//         }
//       ]
//     }
//   ]
// }

$i = 0;
$matchCount = $json->SizeOfArray('match');
while ($i < $matchCount) {
    print 'Match ' . ($i + 1) . ':' . "\n";
    $json->put_I($i);
    $j = 0;
    $numCaptureGroups = $json->SizeOfArray('match[i].group');
    while ($j < $numCaptureGroups) {
        $json->put_J($j);
        $cap = $json->stringOf('match[i].group[j].cap');
        print $j . ': ' . $cap . "\n";
        $j = $j + 1;
    }

    $i = $i + 1;
}

// Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

// Output

// Match 1:
// 0: Name: John Smith, Email: john.smith@example.com
// 1: John
// 2: Smith
// 3: john.smith@example.com

?>