(DataFlex) Regular Expression with Multiple Matches and Capture Groups

See more Regular Expressions Examples

Demonstrates a regular expression with multiple matches and capture groups for each match.

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

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

Chilkat ActiveX Downloads

ActiveX for 32-bit and 64-bit Windows

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    String sPattern
    Handle hoSb
    Boolean iCrlf
    Variant vJson
    Handle hoJson
    Integer iTimeoutMs
    Integer iNumMatches
    String sCap
    Integer i
    Integer iMatchCount
    Integer j
    Integer iNumCaptureGroups
    String sTemp1

    Move False To iSuccess

    Move "Name:\s+(\w+)\s+(\w+),\s+Email:\s+(\S+)" To sPattern

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSb
    If (Not(IsComObjectCreated(hoSb))) Begin
        Send CreateComObject of hoSb
    End
    Move True To iCrlf
    Get ComAppendLine Of hoSb "Name: John Smith, Email: john.smith@example.com" iCrlf To iSuccess
    Get ComAppendLine Of hoSb "Name: Jack Johnson, Email: jack.johnson@example.com" iCrlf To iSuccess
    Get ComAppendLine Of hoSb "Name: Mary Adams, Email: mary.adams@example.com" iCrlf To iSuccess

    Get ComGetAsString Of hoSb To sTemp1
    Showln sTemp1

    // We have the following string:
    // Name: John Smith, Email: john.smith@example.com
    // Name: Jack Johnson, Email: jack.johnson@example.com
    // Name: Mary Adams, Email: mary.adams@example.com

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Set ComEmitCompact Of hoJson To False

    Move 2000 To iTimeoutMs
    Get pvComObject of hoJson to vJson
    Get ComRegexMatch Of hoSb sPattern vJson iTimeoutMs To iNumMatches
    If (iNumMatches < 0) Begin
        // Probably an error in the regular expression.
        // Suggestion: Use AI to help create and/or diagnose regular expressions.
        Get ComLastErrorText Of hoSb To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Examine the matches:
    Get ComEmit Of hoJson To sTemp1
    Showln sTemp1

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

    // {
    //   "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
    //         }
    //       ]
    //     },
    //     {
    //       "group": [
    //         {
    //           "cap": "Name: Jack Johnson, Email: jack.johnson@example.com",
    //           "idx": 49,
    //           "len": 51
    //         },
    //         {
    //           "cap": "Jack",
    //           "idx": 55,
    //           "len": 4
    //         },
    //         {
    //           "cap": "Johnson",
    //           "idx": 60,
    //           "len": 7
    //         },
    //         {
    //           "cap": "jack.johnson@example.com",
    //           "idx": 76,
    //           "len": 24
    //         }
    //       ]
    //     },
    //     {
    //       "group": [
    //         {
    //           "cap": "Name: Mary Adams, Email: mary.adams@example.com",
    //           "idx": 102,
    //           "len": 47
    //         },
    //         {
    //           "cap": "Mary",
    //           "idx": 108,
    //           "len": 4
    //         },
    //         {
    //           "cap": "Adams",
    //           "idx": 113,
    //           "len": 5
    //         },
    //         {
    //           "cap": "mary.adams@example.com",
    //           "idx": 127,
    //           "len": 22
    //         }
    //       ]
    //     }
    //   ]
    // }

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

    Move 0 To i
    Get ComSizeOfArray Of hoJson "match" To iMatchCount
    While (i < iMatchCount)
        Showln "Match " (i + 1) ":"
        Set ComI Of hoJson To i
        Move 0 To j
        Get ComSizeOfArray Of hoJson "match[i].group" To iNumCaptureGroups
        While (j < iNumCaptureGroups)
            Set ComJ Of hoJson To j
            Get ComStringOf Of hoJson "match[i].group[j].cap" To sCap
            Showln j ": " sCap
            Move (j + 1) To j
        Loop

        Move (i + 1) To i
    Loop

    // 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
    // Match 2:
    // 0: Name: Jack Johnson, Email: jack.johnson@example.com
    // 1: Jack
    // 2: Johnson
    // 3: jack.johnson@example.com
    // Match 3:
    // 0: Name: Mary Adams, Email: mary.adams@example.com
    // 1: Mary
    // 2: Adams
    // 3: mary.adams@example.co


End_Procedure