Learn Java Programming - Regex Metacharacters Tutorial
Metacharacters are ordinary characters that cause the compiled regex expression to be interpreted in a special way. The following list of characters are all metacharacters with a brief description of what they commonly do :
. the period is a wildcard for any character (letter, number, symbol, etc.). [] square brackets are used in character classes. () parenthesis are used in capturing groups. {} curly brackets are used in quantifiers. \ the backslash is used to precede a metacharacter or a predefined character class. It is also used to indicate a Java escape sequence character. ^ the caret is used for negation or the beginning of a line. - the dash is used for ranges. & the ampersand is used for intersections. = the equals is used for special construct lookahead. $ the dollar sign is a boundary matcher for the end of a line. ! the exclamation mark is used for special construct lookbehind. | the pipe is used for or expressions. ? the question mark is used in quantifiers and special constructs. * the asterisk is used in quantifiers. + the plus is used in quantifiers. , the comma is used in quantifiers.
