Grouping Constructs
            The following regular expression grouping constructs let you extract a subset of information from a token or text.
| Regular Expression | Description | 
|---|---|
| (expr) | Match or capture group. Captures the information that matches the expression in parentheses | 
| (?:expr) | Non-capturing group. Groups the contained expressions together (e.g., to apply a quantifier to multiple symbols at once), but does not restrict the information to be captured to only that group. | 
| (?=expr) | Captures information that is followed by the expression if the expression is true and the input matches the pattern that follows this expression. | 
| (?<>) | Named capture group.* | 
| \k<> | Named back reference. * |