Second, you use the non-greedy zero-or-one version 'a*?'. It’s greedy so it matches as many 'a' characters as it can. Let’s start with the asterisk (zero-or-more operator): > re.findall('a*', 'aaaa')įirst, you use the zero-or-more asterisk regex 'a*'.

This pattern of first matching the empty string and only then matching the 'a' if it is absolutely needed repeats. But after that, it’s free to match the empty string again. Only then, it cannot match the empty string anymore so it is forced to match the first 'a' character. Note that it moves from left to right so it matches the empty string and “consumes” it. In the second instance, you use the non-greedy zero-or-one version 'a?'. It’s greedy so it matches one 'a' character if possible. In the first instance, you use the zero-or-one regex 'a?'. Let’s start with the question mark (zero-or-one operator): > import re

Here are some examples that show how non-greedy matching works: Non-Greedy Question Mark Operator (?) they “consume” or match as few characters as possible so that the regex pattern is still satisfied. If you’re a busy person, here’s the short version of this tutorial:Ī greedy quantifier such as ?, *, +, and ?.

Notepad++ regex not greedy