C# - Character Escapes


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These are basically the special characters or escape characters. The backslash character (\) in a regular expression indicates that the character that follows it either is a special character or should be interpreted literally.

The following table lists the escape characters:

Escape character Description Pattern Matches
\a Matches a bell character, \u0007. \a "\u0007" in "Warning!" + '\u0007'
\b In a character class, matches a backspace, \u0008. [\b]{3,} "\b\b\b\b" in "\b\b\b\b"
\t Matches a tab, \u0009. (\w+)\t "Name\t", "Addr\t" in "Name\tAddr\t"
\r Matches a carriage return, \u000D. (\r is not equivalent to the newline character, \n.) \r\n(\w+) "\r\nHello" in "\r\Hello\nWorld."
\v Matches a vertical tab, \u000B. [\v]{2,}"\v\v\v" in "\v\v\v"
\f Matches a form feed, \u000C. [\f]{2,} "\f\f\f" in "\f\f\f"
\n Matches a new line, \u000A. \r\n(\w+) "\r\nHello" in "\r\Hello\nWorld."
\e Matches an escape, \u001B. \e "\x001B" in "\x001B"
\nnn Uses octal representation to specify a character (nnn consists of up to three digits). \w\040\w "a b", "c d" in "a bc d"
\x nn Uses hexadecimal representation to specify a character (nn consists of exactly two digits). \w\x20\w "a b", "c d" in "a bc d"
\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. \cC "\x0003" in "\x0003" (Ctrl-C)
\u nnnn Matches a Unicode character by using hexadecimal representation (exactly four digits, as represented by nnnn). \w\u0020\w "a b", "c d" in "a bc d"
\ When followed by a character that is not recognized as an escaped character, matches that character. \d+[\+-x\*]\d+\d+[\+-x\*\d+ "2+2" and "3*9" in "(2+2) * 3*9"

csharp_regular_expressions.htm

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