Python re module usage

Python's re module is one of the core modules for regular expression operations. Commonly used methods are: 1. re.match, try to match the pattern from the starting position of the string; 2. re.search, search for the pattern in the string; 3. re.findall, return all content in the string that matches the pattern list; 4. re.finditer, returns an iterator of all content matching the pattern in the string; 5. re.split, splits the string into multiple parts according to the matching splitting rules, etc.