regex - Carets in Regular Expressions - Stack Overflow 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
Regex: ?: notation (Question mark and colon notation) 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
regex - What is the difference between . *? and . * regular expressions . . . Repetition in regex by default is greedy: they try to match as many reps as possible, and when this doesn't work and they have to backtrack, they try to match one fewer rep at a time, until a match of the whole pattern is found As a result, when a match finally happens, a greedy repetition would match as many reps as possible
regex - How to match any character in regular expression? - Stack . . . 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
Regex that accepts only numbers (0-9) and NO characters 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 well as "A9B", but the regex ^[0-9]$ only matches "9"
regex - Regular Expressions: Is there an AND operator? - Stack Overflow 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
regex - Regular Expression with wildcards to match any character . . . 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 unescaped parentheses from the regex, then isolate the part of the regex that you want to put in a group and wrap it in parentheses Groups are evaluated from left to right so if you want something to be in the second
regex - Match linebreaks - \n or \r\n? - Stack Overflow 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
OR condition in Regex - Stack Overflow 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 search for a new match, so to speak