\w - word character: letter, number and underscore characters\W - not word character\d - digits\D - not digits\s - whitespace\S - not whitespace. - any character except line breaks[abc] - character set[^abc] - negated character set[a-z] - range{1,3} - quantifier range\* - expression matches 0 or more\+ - expression matches 1 or more? - optional( ) - groups an expression\\ - escape character^ - select at line start$ - select at line end(?=) - positive lookahead Ex. \d+(?=PM) to get 3 in 4 Aug 3 PM(!?) - negative lookahead (select characters other than those containing...) Ex. \d+(!?PM) to get 4 in 4 Aug 3 PM(?<=) - positive lookbehind (select characters that are preceeded by ...) Ex. (?<=\$)\d+ to get 5 in Product Code: 1064 Price: $5(?<!<) - negative lookbehind (select characters other than those preceeded by ...)
Links to tutorials