Greedy and lazy quantifiers

All the quantifiers that we discussed so far are greedy. A greedy quantifier starts looking at the entire string for a match. If there are no matches, it removes the last character in the string and reattempts the match. If a match is not found again, the last character is again removed and the process is repeated until a match is found or the string is left with no characters.

The \d+ pattern, for example, will match one or more digits. For example, if your string is 123, a greedy match would match 1, 12, and 123. Greedy pattern h.+l would match hell in a string hello—which is the longest possible string match. As \d+ is greedy, it will match as many digits as possible and hence the match would be 123.

In contrast to greedy quantifiers, a lazy quantifier matches as few of the quantified tokens as possible. You can add a question mark (?) to the regular expression to make it lazy. A lazy pattern h.?l would match hel in the string hello—which is the shortest possible...