Escaped character

Description

\a

Matches a bell character, \u0007.

\b

In a character class, matches a backspace, \u0008.

\t

Matches a tab, \u0009.

\r

Matches a carriage return, \u000D. (\r is not equivalent to the newline character, \n.)

\v

Matches a vertical tab, \u000B.

\f

Matches a form feed, \u000C.

\n

Matches a new line, \u000A.

\e

Matches an escape, \u001B.

\ nnn

Uses octal representation to specify a character (nnn consists of two or three digits).

\x nn

Uses hexadecimal representation to specify a character (nn consists of exactly two digits).

\c X

\c x

Matches the ASCII control character that is specified by X or x, where X or x is the letter of the control character.

\u nnnn

Matches a Unicode character by using hexadecimal representation (exactly four digits, as represented by nnnn).

\

When followed by a character that is not recognized as an escaped character in this and other tables in this topic, matches that character. For example, \* is the same as\x2A, and \. is the same as \x2E. This allows the regular expression engine to disambiguate language elements (such as * or ?) and character literals (represented by \* or\?).

Pattern

Matches

\a

"\u0007" in "Error!" + '\u0007'

[\b]{3,}

"\b\b\b\b" in "\b\b\b\b"

(\w+)\t

"item1\t", "item2\t" in "item1\titem2\t"

\r\n(\w+)

"\r\nThese" in "\r\nThese are\ntwo lines."

[\v]{2,}

"\v\v\v" in "\v\v\v"

[\f]{2,}

"\f\f\f" in "\f\f\f"

\r\n(\w+)

"\r\nThese" in "\r\nThese are\ntwo lines."

\e

"\x001B" in "\x001B"

\w\040\w

"a b", "c d" in

"a bc d"

\w\x20\w

"a b", "c d" in

"a bc d"

\cC

"\x0003" in "\x0003" (Ctrl-C)

\w\u0020\w

"a b", "c d" in

"a bc d"

\d+[\+-x\*]\d+\d+[\+-x\*\d+

"2+2" and "3*9" in "(2+2) * 3*9"