11.4. Matching, substring captures, and MatchData
So far, we’ve looked at basic match operations:
regex.match(string) string.match(regex)
These are essentially true/false tests: either there’s a match or there isn’t. Now we’ll examine what happens on successful and unsuccessful matches and what a match operation can do for you beyond the yes/no answer.
11.4.1. Capturing submatches with parentheses
One of the most important techniques of regexp construction is the use of parentheses to specify captures.
The idea is this. When you test for a match between a string—say, a line from a file—and a pattern, it’s usually because you want to do something with the string or, more commonly, with part of the string. The capture notation allows you to isolate ...
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