How can you filter a list in Python using an arbitrary condition? The most Pythonic and most performant way is to use list comprehension [x for x in list if condition] to filter all elements from a list. Filter with List Comprehension The most Pythonic way of filtering a list—in my opinion—is the list comprehension …
Today, I stumbled upon this beautiful regex problem: Given is a multi-line string and a regex pattern. How to find all lines that do NOT contain the regex pattern? I’ll give you a short answer and a long answer. The short answer is to use the pattern ‘((?!regex).)*’ to match all lines that do not …
How to Find All Lines Not Containing a Regex in Python? Read More »
This morning, I read over an actual Quora thread with this precise question. While there’s no dumb question, the question reveals that there may be some gap in understanding the basics in Python and Python’s regular expression library. So if you’re an impatient person, here’s the short answer: How to match an exact word/string using …
How to Match an Exact Word in Python Regex? (Answer: Don’t) Read More »
The web is full of tutorials about regular expressions. But I realized that most of those tutorials lack a thorough motivation. Why do regular expressions exist? What are they used for? What are some practical applications? Somehow, the writers of those tutorials believe that readers are motivated by default to learn a technology that’s complicated …
What are Regular Expressions Used For? 10 Applications Read More »
This tutorial explains everything you need to know about matching groups in Python’s re package for regular expressions. You may have also read the term “capture groups” which points to the same concept. As you read through the tutorial, you can also watch the tutorial video where I explain everything in a simple way: Related …
Ready to earn the black belt of your regex superpower? This tutorial shows you the subtle but important difference between greedy and non-greedy regex quantifiers. You can also watch the explainer video I created for this article: If you’re a busy person, here’s the short version of this tutorial: Definition Greedy Quantifier: A greedy quantifier …
This tutorial makes you a master of character sets in Python. (I know, I know, it feels awesome to see your deepest desires finally come true.) As I wrote this article, I saw a lot of different terms describing this same powerful concept such as “character class“, “character range“, or “character group“. However, the most …
A regular expression is a decades-old concept in computer science. Invented in the 1950s by famous mathematician Stephen Cole Kleene, the decades of evolution brought a huge variety of operations. Collecting all operations and writing up a comprehensive list would result in a very thick and unreadable book by itself. Related article: Python Regex Superpower …
Python’s re module comes with a number of regular expression methods that help you achieve more with less. Related article: Python Regex Superpower – The Ultimate Guide Think of those methods as the framework connecting regular expressions with the Python programming language. Every programming language comes with its own way of handling regular expressions. For …
What’s the best-kept productivity secret of code masters? Here’s what ex-Google’s tech lead says is the most important skill as a coder (spoiler: it has to do with the topic of the tutorial): Congratulations – you’re about to become a regular expression master. I’ve not only written the most comprehensive free regular expression tutorial on …
This tutorial is all about the AND operator of Python’s re library. You may ask: what? (And rightly so.) Sure, there’s the OR operator (example: ‘iPhone|iPad’). But what’s the meaning of matching one regular expression AND another? There are different interpretations for the AND operator in a regular expression (regex): Ordered: Match one regex pattern after …
This tutorial is all about the or | operator of Python’s re library. You can also play the tutorial video while you read: Related article: Python Regex Superpower – The Ultimate Guide What’s the Python Regex Or | Operator? Given a string. Say, your goal is to find all substrings that match either the string ‘iPhone’ …
