regular expressions debugging python has some simple and rudimentary built-in documentation that can be quite helpful if you need quick refresher to trigger your memory about the exact name of particular method this documentation can be viewed in the python interpreter in interactive mode you can bring up an interactive help system using help(help(helpmodules if you know what module you want to useyou can use the dir(command to find the methods in the module as followsimport re dir(re'compile''copy_reg''error''escape''findall''finditer'match''purge''search''split''sre_compile''sre_parse'sub''subn''sys''template'you can also get small amount of documentation on particular method using the dir command help (re searchhelp on function search in module research(patternstringflags= scan through string looking for match to the patternreturning match objector none if no match was found the built-in documentation is not very extensivebut it can be helpful when you are in hurry or don' have access to web browser or search engine glossary brittle code code that works when the input data is in particular format but is prone to breakage if there is some deviation from the correct format we call this "brittle codebecause it is easily broken greedy matching the notion that the and characters in regular expression expand outward to match the largest possible string grep command available in most unix systems that searches through text files looking for lines that match regular expressions the command name stands for "generalized regular expression parser