PHP ActiveX Requires Chilkat v11.1.0+

Regular Expression Replace Capture Groups

See more Regular Expressions Examples

Demonstrates replacing capture groups for a regular expression.

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

PHP ActiveX

<?php

$success = 0;

$subject = 'John Anders, +_+_+ Mary Robins $$$$';
$pattern = '(?<first>\\w+)\\s+(?<last>\\w+)';

$sb = new COM("Chilkat.StringBuilder");
$sb->Append($subject);

$json = new COM("Chilkat.JsonObject");
$json->EmitCompact = 0;

$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";

//  There are 2 matches:

//  {
//    "named": {
//      "first": 1,
//      "last": 2
//    },
//    "match": [
//      {
//        "group": [
//          {
//            "cap": "John Anders",
//            "idx": 0,
//            "len": 11
//          },
//          {
//            "cap": "John",
//            "idx": 0,
//            "len": 4
//          },
//          {
//            "cap": "Anders",
//            "idx": 5,
//            "len": 6
//          }
//        ]
//      },
//      {
//        "group": [
//          {
//            "cap": "Mary Robins",
//            "idx": 19,
//            "len": 11
//          },
//          {
//            "cap": "Mary",
//            "idx": 19,
//            "len": 4
//          },
//          {
//            "cap": "Robins",
//            "idx": 24,
//            "len": 6
//          }
//        ]
//      }
//    ]
//  }

//  To replace capture groups, write code to examine each capture group within
//  each match, and provide a replacement string.
//  Then call RegexReplace.

//  For example, let's capitalize the first names, and add append "on" to the last name.
//  After doing replacements, we should get:  JOHN Anderson, +_+_+ MARY Robinson $$$$

$firstNameIdx = $json->IntOf('named.first');
$lastNameIdx = $json->IntOf('named.last');

$sbTemp = new COM("Chilkat.StringBuilder");

$i = 0;
$numMatches = $json->SizeOfArray('match');
while ($i < $numMatches) {

    $json->I = $i;

    //  The replacement string for the first name will be all uppercase.
    $json->J = $firstNameIdx;
    $sbTemp->Clear();
    $json->StringOfSb('match[i].group[j].cap',$sbTemp);
    $sbTemp->ToUppercase();
    $json->UpdateSb('match[i].group[j].rep',$sbTemp);

    //  Append "on" to the last name.
    $json->J = $lastNameIdx;
    $sbTemp->Clear();
    $json->StringOfSb('match[i].group[j].cap',$sbTemp);
    $sbTemp->Append('on');
    $json->UpdateSb('match[i].group[j].rep',$sbTemp);

    $i = $i + 1;
}

//  The JSON now has replacement strings:
print $json->emit() . "\n";

//  {
//    "named": {
//      "first": 1,
//      "last": 2
//    },
//    "match": [
//      {
//        "group": [
//          {
//            "cap": "John Anders",
//            "idx": 0,
//            "len": 11
//          },
//          {
//            "cap": "John",
//            "idx": 0,
//            "len": 4,
//            "rep": "JOHN"
//          },
//          {
//            "cap": "Anders",
//            "idx": 5,
//            "len": 6,
//            "rep": "Anderson"
//          }
//        ]
//      },
//      {
//        "group": [
//          {
//            "cap": "Mary Robins",
//            "idx": 19,
//            "len": 11
//          },
//          {
//            "cap": "Mary",
//            "idx": 19,
//            "len": 4,
//            "rep": "MARY"
//          },
//          {
//            "cap": "Robins",
//            "idx": 24,
//            "len": 6,
//            "rep": "Robinson"
//          }
//        ]
//      }
//    ]
//  }

//  Call RegexReplace to update the StringBuilder with the replacements.
$success = $sb->RegexReplace($json);
if ($success == 0) {
    print $sb->LastErrorText . "\n";
    exit;
}

print 'Result after doing replacements:' . "\n";
print $sb->getAsString() . "\n";

//  Result after doing replacements:
//  JOHN Anderson, +_+_+ MARY Robinson $$$$

?>