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 concluded it means the former a...
How do I make an expression to match absolutely anything (including whitespaces)? Example: Regex: I bought _____ sheep. Matches: I bought sheep. I bought a sheep. I bought five sheep. I tried usi...
It indicates that the subpattern is a non-capture subpattern. That means whatever is matched in (?:\w+\s), even though it's enclosed by () it won't appear in the list of matches, only (\w+) will. You're still looking for a specific pattern (in this case, a single whitespace character following at least one word), but you don't care what's actually matched.
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 use a character class such as [\s\S] to match any character. This character matches a character that is either a whitespace character (including line break characters), or a character that is not a whitespace character ...
In regex in general, ^ is negation only at the beginning of a character class. Unless CMake is doing something really funky (to the point where calling their pattern matching language "regex" could be regarded as misleading or incorrect) I'm guessing the fact that it worked for you was an isolated accident.
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 them enough. thank you
Now, when the regex engine tries to match against aaaaaaaab, the .* will again consume the entire string. However, since the engine will have reached the end of the string and the pattern is not yet satisfied (the .* consumed everything but the pattern still has to match b afterwards), it will backtrack, one character at a time, and try to match b.
If you're looking to capture everything up to "abc": /^(.*?)abc/ Explanation: ( ) capture the expression inside the parentheses for access using $1, $2, etc. ^ match start of line .* match anything, ? non-greedily (match the minimum number of characters required) - [1] [1] The reason why this is needed is that otherwise, in the following string: whatever whatever something abc something abc by ...
While writing this answer, I had to match exclusively on linebreaks instead of using the s-flag (dotall - dot matches linebreaks). The sites usually used to test regular expressions behave diffe...
