Jun 1, 2017 · Specifically when does ^ mean "match start" and when does it mean "not the following" in regular expressions? From the Wikipedia article and other references, I've …

Dec 8, 2018 · The regex compiles fine, and there are already JUnit tests that show how it works. It's just that I'm a bit confused about why the first question mark and colon are there.

In case it is JS it indicates the start and end of the regex, like quotes for strings. stackoverflow.com/questions/15661969/…

Apr 7, 2011 · I'm reading the regular expressions reference and I'm thinking about ? and ?? characters. Could you explain me with some examples their usefulness? I don't understand …

The regex [a-z] will match any letter a through z. The () construct is a grouping construct establishing a precedence order (it also has impact on accessing matched substrings but …

Jul 30, 2013 · Just a pedantic adjustment to what most answers are saying here: [\s\t] is redundant. The \t is already part of \s so you don't have to include the \t. In the case of \s\t, the …

Feb 24, 2023 · For reference, from regular-expressions.info/dot.html: "JavaScript and VBScript do not have an option to make the dot match line break characters. In those languages, you can …

Aug 18, 2010 · What is also important there is that regex with non-capturing groups (?: is much faster than the same regex with capturing groups ' ('. So we should use non-capturing groups …

By putting ^ at the beginning of your regex and $ at the end, you ensure that no other characters are allowed before or after your regex. For example, the regex [0-9] matches the strings "9" as …

Apr 13, 2013 · Note that your regex would have worked too if it was written as \d \w|\d instead of \d|\d \w. This is because in your case, once the regex matches the first option, \d, it ceases to …