match class : Group(int) method
Description
Gets a substring that matches the regular expression group selected by the index.
Syntax
matchInstance.Group(int index)
Arguments
| Class | Name | Description |
| int | index | A index. |
Return value
| Class | Description |
| string | A substring that matches the regular expression group selected by the index. |
Sample code
| 1: | regex pattern = new regex("(\d)(\d)"); // There are groups in the regular expression. |
| 2: | match firstMatch= pattern.MatchM("ww1245cc66"); // It matches to "12". |
| 3: | int count = firstMatch.GroupCount; // The GroupCount is 3. "12", "1", and "2" |
| 4: | string resultStr = firstMatch.Group(0); // "12" |
| 5: | resultStr = firstMatch.Group(1); // "1" |
| 6: | resultStr = firstMatch.Group(2); // "2" |
| 7: | // --------------------------------------------------------------------------------- |
| 8: | pattern = new regex("\d\d"); // There is no group in the regular expression. |
| 9: | firstMatch= pattern.MatchM("ww1245cc66"); // It matches to "12". |
| 10: | count = firstMatch.GroupCount; // The GroupCount is 1. The matched substring is also group. |
| 11: | resultStr = firstMatch.Group(0); // "12" |
| 12: | // --------------------------------------------------------------------------------- |
| 13: | firstMatch= pattern.MatchM("wwwwwww"); // It does not match. |
| 14: | count = firstMatch.GroupCount; // Still, the GroupCount is 1. |
| 15: | resultStr = firstMatch.Group(0); // "" |
Notes
It's a wrapper of the System.Text.RegularExpressions.Match.Groups property.
The index is 0-based.
The result of matchInstance.Group (0) is always an entire substring.
If the match is successful, the entire matched substring is also recognized as a group, so executing matchInstance.Group (0) will return the entire substring.
If the match is failure, there is no matched substring, so executing matchInstance.Group (0) will return an empty string.