On greedy vs non-greedy. 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 …

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 differences …

Aug 17, 2022 · What does \\d+ mean in a regular expression?

Oct 3, 2010 · A possessive quantifier is an advanced feature of some regex flavours (PCRE, Java and the JGsoft engine) which tells the engine not to backtrack once a match has been made. …

I need a regex that will accept only digits from 0-9 and nothing else. No letters, no characters. I thought this would work: ^[0-9] or even \d+ but these are accepting the characters : ^,$,(,), etc. …

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 …

May 14, 2019 · regex in javascript, match only A-z and _? 6 Regular Expression to validate only A-Z, a-z, 0-9, space, period, hyphen - exclamation mark ! question mark ? quotes "

Apr 13, 2013 · A classic "or" would be |.For example, ab|de would match either side of the expression. However, for something like your case you might want to use the ? quantifier, …

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. In this …

Feb 11, 2022 · Quick answer: ^[\w*]$ will match a string consisting of a single character, where that character is alphanumeric (letters, numbers) an underscore (_) or an asterisk (*).