To count a regex pattern multiple times in a given string, use the method len(re.findall(pattern, string)) that returns the number of matching substrings or len([*re.finditer(pattern, text)]) that unpacks all matching substrings into a list and returns the length of it as well. A few hours ago, I wrote a regular expression in Python that matched … Read more
Just like me an hour ago, you’re probably sitting in front of your regular expression code, puzzled by a strange error message: Why is it raised? Where does it come from? And, most importantly, how can you get rid of it? This article gives you answers to all of those questions. Alternatively, you can also … Read more
When I first learned about regular expressions, I didn’t really appreciate their power. But there’s a reason regular expressions have survived seven decades of technological disruption: coders who understand regular expressions have a massive advantage when working with textual data. They can write in a single line of code what takes others dozens! This article … Read more
Why have regular expressions survived seven decades of technological disruption? Because coders who understand regular expressions have a massive advantage when working with textual data. They can write in a single line of code what takes others dozens! This article is all about the re.match() method of Python’s re library. There are two similar methods to … Read more
Why have regular expressions survived seven decades of technological disruption? Because coders who understand regular expressions have a massive advantage when working with textual data. They can write in a single line of code what takes others dozens! This article is all about the re.fullmatch(pattern, string) method of Python’s re library. There are three similar methods … Read more
The method re.compile(pattern) returns a regular expression object from the pattern that provides basic regex methods such as pattern.search(string), pattern.match(string), and pattern.findall(string). The explicit two-step approach of (1) compiling and (2) searching the pattern is more efficient than calling, say, search(pattern, string) at once, if you match the same pattern multiple times because it avoids … Read more
In many Python regex functions, you see a third argument flags. What are they and how do they work? Flags allow you to control the regular expression engine. Because regular expressions are so powerful, they are a useful way of switching on and off certain features (e.g. whether to ignore capitalization when matching your regex). … Read more
I’m always surprised how regular expressions survived seven decades of technological disruption. They look much the same as 70 years ago. This means that if you master regular expressions, you build yourself a lasting and highly relevant skill in today’s marketplace. You’ll be able to write in a single line of code what takes others … Read more
Do you want to replace all occurrences of a pattern in a string? You’re in the right place! The regex function re.sub(P, R, S) replaces all occurrences of the pattern P with the replacement R in string S. It returns a new string. For example, if you call re.sub(‘a’, ‘b’, ‘aabb’), the result will be … Read more
When I first learned about regular expressions, I didn’t appreciate their power. But there’s a reason regular expressions have survived seven decades of technological disruption: coders who understand regular expressions have a massive advantage when working with textual data. They can write in a single line of code what takes others dozens! This article is … Read more
Congratulations, you’re about to learn one of the most frequently used regex operators: the question mark quantifier A?. In particular, this article is all about the ? quantifier in Python’s re library. You can also watch the explainer video while you skim through the tutorial: Related article: Python Regex Superpower – The Ultimate Guide What’s the … Read more
You’re about to learn one of the most frequently used regex operators: the dot regex . in Python’s re library. You can also watch the walk-through video as you read through the tutorial: Related article: Python Regex Superpower – The Ultimate Guide What’s the Dot Regex in Python’s Re Library? The dot regex . matches … Read more