Word boundaries in regex

Matching strings as whole words might sound trivial, but did you know that "__1__" is a valid "word" for a regex? That "\bext\b" won't find a match in "_ext_"? Do you know that "\b" is not the only way to define word boundaries? Check out this video to learn the basics of regex word boundaries. Besides, you will learn that there are other types of "boundaries" that you can define with the help of lookarounds.

REGEX FIDDLE: https://regex101.com/r/ZKrnJX/2/

When using word boundaries in your code, make sure the backslashes are escaped properly (use raw/verbatim string literals to avoid issues). Check if necessary flags are used for Unicode ("u" flag in PHP, for example).

FURTHER LINKS
Word Boundaries: https://www.regular-expressions.info/...
Adaptive word boundaries for dynamic regexps: https://stackoverflow.com/a/68467672/...
Unicode word boundary in JavaScript: https://stackoverflow.com/a/66680311/...
Match a whole word with dynamic Python regex: https://stackoverflow.com/a/29996092/...
Word boundaries in R: https://stackoverflow.com/q/6528258/3...
Match entire words only: https://stackoverflow.com/q/1751301/3...
Tcl/MySQL/POSIX word boundaries (capitalized words): https://stackoverflow.com/a/61795844/...