Many patterns include atoms that repeat multiple times. For example, to match a string with 6 letters one might define the pattern:

\w\w\w\w\w\w

which is both cumbersome, and limits the pattern to only a specific number of characters. What if we wanted to match words with 6 or 7 letters?

This is resolved using quantifiers, which specify how atoms repeat in a pattern. Using quantifiers we could express the previous pattern as:

\w\{6}

which specifies that the "\w" atom is to be repeated 6 times.

Greedy vs Non-greedy

Greedy matching is the default behavior of regular expressions, where the regular expression engine will try to match as much text as possible. In contrast, non-greedy matching, also known as lazy matching, tries to match as little text as possible.