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 …

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

Jan 2, 1999 · Parentheses in regular expressions define groups, which is why you need to escape the parentheses to match the literal characters. So to modify the groups just remove all of the …

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 …

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 …

64 A simple and cheap regex that will never match anything is to match against something that is simply unmatchable, for example: \b\B. It's simply impossible for this regex to match, since it's …

I need to extract from a string a set of characters which are included between two delimiters, without returning the delimiters themselves. A simple example should be helpful: Target: …

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 …

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 …

Nov 12, 2009 · I need a regex which will allow only A-Z, a-z, 0-9, the _ character, and dot (.) in the input. I tried: [A-Za-z0-9_.] But, it did not work. How can I fix it?