Oct 15, 2009 · May I know what ?= means in a regular expression? For example, what is its significance in this expression: (?=.*\\d).

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.

Be aware that the first ^ in this answer gives the regex a completely different meaning: It makes the regular expression look only for matches starting from the beginning of the string.

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 …

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

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: …

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 …

Jan 22, 2009 · 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 …

Oct 5, 2022 · I am using a regex to program an input validator for a text box where I only want alphabetical characters. I was wondering if [A-z] and [a-zA-Z] were equivalent or if there were …

Oct 5, 2008 · The RegEx of accepted answer returns the values including their sourrounding quotation marks: "Foo Bar" and "Another Value" as matches. Here are RegEx which return …