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Character Escapes 

Most of the important regular expression language operators are unescaped single characters. The escape character \ (a single backslash) signals to the regular expression parser that the character following the backslash is not an operator. For example, the parser treats an asterisk (*) as a repeating quantifier and a backslash followed by an asterisk (\*) as the Unicode character 002A.

The character escapes listed in this table are recognized both in regular expressions and in replacement patterns.

Escaped character Description

ordinary characters

Characters other than . $ ^ { [ ( | ) * + ? \ match themselves.

\a

Matches a bell (alarm) \u0007.

\b

Matches a backspace \u0008 if in a [] character class; otherwise, see the note following this table.

\t

Matches a tab \u0009.

\r

Matches a carriage return \u000D.

\v

Matches a vertical tab \u000B.

\f

Matches a form feed \u000C.

\n

Matches a new line \u000A.

\e

Matches an escape \u001B.

\040

Matches an ASCII character as octal (up to three digits); numbers with no leading zero are backreferences if they have only one digit or if they correspond to a capturing group number. (For more information, see Backreferences.) For example, the character \040 represents a space.

\x20

Matches an ASCII character using hexadecimal representation (exactly two digits).

\cC

Matches an ASCII control character; for example, \cC is control-C.

\u0020

Matches a Unicode character using hexadecimal representation (exactly four digits).

NoteNote

The Perl 5 character escape that is used to specify Unicode is not supported by the .NET Framework. The Perl 5 character escape is of the form \x{####…}, where "####…" is a series of hexadecimal digits. Instead, use the .NET Framework character escape described in this row.

\

When followed by a character that is not recognized as an escaped character, matches that character. For example, \* is the same as \x2A.

NoteNote

The escaped character \b is a special case. In a regular expression, \b denotes a word boundary (between \w and \W characters) except within a [] character class, where \b refers to the backspace character. In a replacement pattern, \b always denotes a backspace.

See Also

Other Resources

Regular Expression Language Elements