.Any character except newline\dDigit (0-9)\DNon-digit\wWord character (a-z, A-Z, 0-9, _)\WNon-word character\sWhitespace\SNon-whitespace[abc]Character set (a, b, or c)[^abc]Negated set (not a, b, or c)[a-z]Character range*0 or more+1 or more?0 or 1 (optional){3}Exactly 3{3,}3 or more{3,5}Between 3 and 5*?0 or more (lazy)+?1 or more (lazy)??0 or 1 (lazy)^Start of string/line$End of string/line\bWord boundary\BNon-word boundary\AStart of string\ZEnd of string(abc)Capturing group(?:abc)Non-capturing group(?=abc)Positive lookahead(?!abc)Negative lookahead(?<=abc)Positive lookbehind(?Negative lookbehinda|bAlternation (a or b)[\w\.-]+@[\w\.-]+\.[a-zA-Z]{2,}https?://[\w\.-]+\.[a-zA-Z]{2,}[/\w\.-]*/?.*$$?(\d{3})$$?[-.\s]?(\d{3})[-.\s]?(\d{4})(?:\d{1,3}\.){3}\d{1,3}\d{1,2}/\d{1,2}/\d{4}[0-2]?\d:[0-5]\d