Go

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

Go

    success := false

    pattern := "Name:\\s+(\\w+)\\s+(\\w+),\\s+Email:\\s+(\\S+)"

    sb := chilkat.NewStringBuilder()
    crlf := true
    sb.AppendLine("Name: John Smith, Email: john.smith@example.com",crlf)
    sb.AppendLine("Name: Jack Johnson, Email: jack.johnson@example.com",crlf)
    sb.AppendLine("Name: Mary Adams, Email: mary.adams@example.com",crlf)

    fmt.Println(*sb.GetAsString())

    // 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

    json := chilkat.NewJsonObject()
    json.SetEmitCompact(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.
        fmt.Println(sb.LastErrorText())
        sb.DisposeStringBuilder()
        json.DisposeJsonObject()
        return
    }

    // Examine the matches:
    fmt.Println(*json.Emit())

    // 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.

    var cap *string = new(string)
    i := 0
    matchCount := json.SizeOfArray("match")
    for i < matchCount {
        fmt.Println("Match ", i + 1, ":")
        json.SetI(i)
        j := 0
        numCaptureGroups := json.SizeOfArray("match[i].group")
        for j < numCaptureGroups {
            json.SetJ(j)
            cap = json.StringOf("match[i].group[j].cap")
            fmt.Println(j, ": ", *cap)
            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
    // 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

    sb.DisposeStringBuilder()
    json.DisposeJsonObject()