.NET Core C#

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

.NET Core C#

bool success = false;

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

Chilkat.StringBuilder sb = new Chilkat.StringBuilder();
bool 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);

Debug.WriteLine(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

Chilkat.JsonObject json = new Chilkat.JsonObject();
json.EmitCompact = false;

int timeoutMs = 2000;
int 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.
    Debug.WriteLine(sb.LastErrorText);
    return;
}

// Examine the matches:
Debug.WriteLine(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.

string cap;
int i = 0;
int matchCount = json.SizeOfArray("match");
while (i < matchCount) {
    Debug.WriteLine("Match " + Convert.ToString(i + 1) + ":");
    json.I = i;
    int j = 0;
    int numCaptureGroups = json.SizeOfArray("match[i].group");
    while (j < numCaptureGroups) {
        json.J = j;
        cap = json.StringOf("match[i].group[j].cap");
        Debug.WriteLine(Convert.ToString(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