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What is B in regex?
The metacharacter \b is an anchor like the caret and the dollar sign. It matches at a position that is called a “word boundary”. Before the first character in the string, if the first character is a word character. After the last character in the string, if the last character is a word character.
What is word boundary in regex?
A word boundary, in most regex dialects, is a position between \w and \W (non-word char), or at the beginning or end of a string if it begins or ends (respectively) with a word character ( [0-9A-Za-z_] ). So, in the string “-12” , it would match before the 1 or after the 2. The dash is not a word character.
Why are regular expressions so hard to write?
Regular expressions are very powerful, but they have one small and one big problem; they are hard to write, and near impossible to read. In a best case the use of the regular expression solves the problem, so then you only have the maintenance problem of the complicated code.
Who is Jamie Zawinski and what did he do?
Jamie Zawinski ( JWZ; born November 3, 1968) is a computer programmer known for significant contributions to the free software projects Mozilla and XEmacs, and early versions of the Netscape Navigator web browser. Some people, when confronted with a problem, think “I know, I’ll use regular expressions.”
When do you need to use a regex?
This means that, if you decide to use a regex you now have two problems: The original problem you wanted to solve. The support of a regex. Basically, I think he means you should only use a regex if there’s no other way of solving your problem.
How are regular expressions used to maintain software?
The key to maintaining software is writing maintainable code. Using regular expressions can be counter to that goal. When working with regular expressions, you’ve written a mini computer (specifically a non-deterministic finite state automaton) in a special domain specific language.