I'm trying to handle a bunch of files, and I need to alter then to remove extraneous information in the filenames; notably, I'm trying to remove text inside parentheses. For example: filename = " More on stackoverflow.com

IMHO making eyes glaze over is what regular expressions excels at. I hate it with a passion. That being said, it is a powerful, useful tool for parsing text. The key thing that triggered my understanding of regex is that all characters/arguments/etc are positional. They aren't flags, triggers, or what have you, they match the literal of what they represent at that position in your regex string. So, a quick example. I use this in a script of mine for grabbing a version string. "^[0-9]+\.[0-9]+\.[0-9]+" It literally matches start of line, one or more of the digits of zero through nine, a period, one or more digits of zero through nine, a period, one or more digits of zero through nine The carat ^ matches the literal start of line. [0-9] is a kind of specified wildcard, it says the character here can match any digit zero through nine. + is a special character that extends the previous argument in the string ([0-9]) and says to match it at least once and then for as many times as it positively matches. \ is the escape character, it says 'treat the following argument as a string literal, not as a special character'. . since it was escaped by \, we are looking for a literal period/decimal-point. From there, the sequence repeats. It will match any of these, and more: 1.0.5, 15.154.42, 0.0.5 I'm not on my computer with my scripts so I don't have the actual function it's used in handy. I really struggled hard to wrap my head around regular expressions, and I really hope this helps. If you want, I'll come back later when I have access to my scripts and post some actual in-use functions. More on reddit.com

Your regex is: First Name: (.*?) Last Name: (.*?) You are searching for the left-most match in the input: First Name: Gideon Last Name: Asiak So the regex engine consumes First Name:, then consumes as little as possible until Last Name: matches (saving Gideon in group 1), and then gets to match .*? against the remaining Asiak. As this is a non-greedy match, this pattern will consume as little as possible until we get a match. The pattern is already satisfied when consuming zero characters, so group 2 will contain the empty string. How to fix this: If you want to make sure that the entire string matches a pattern, use the fullmatch() function. Equivalently, you could anchor the pattern at the end of the string via the \z assertion. You could use a greedy match for the second group, e.g. (.*). It will consume as much as possible. In practice, if we can assume that each name won't contain spaces, I might write the pattern like this: First Name: (\S+) Last Name: (\S+). That is, use a more specific character class like \S (all non-space characters), and a quantifier that expects at least one character. More on reddit.com

Regex is a mini-programming language by itself. It is powerful and useful if you are doing a lot of text processing. Like a programming language, it will take time and practice to get comfortable with it. There are various online tools that can help you with learning, writing and debugging regex. regex101 — visual aid and online testing tool for regular expressions, select flavor as Python before use debuggex — railroad diagrams for regular expressions, select flavor as Python before use Other useful resources: Awesome Regex — curated collection of libraries, tools, frameworks and software PythonVerbalExpressions — construct regular expressions with natural language terms CommonRegex — collection of common regular expressions stackoverflow: regex FAQ More on reddit.com