Scripting Guide > Types of Data > Regular Expressions > Special Characters in Regular Expressions
Publication date: 12/18/2019

Special Characters in Regular Expressions

Special characters are commonly used in regular expressions. The period is a special character that matches one instance of the specified character. It must be escaped with a backslash to be interpreted as a period. In the following expression, the period is replaced with an exclamation point.

Regex( "Bicycling makes traveling to work fun.", "\.", "!", GLOBALREPLACE );

"Bicycling makes traveling to work fun!"

Table 6.8 describes the special characters and provides examples.

Table 6.8 Special Characters in Regular Expressions

\

Precedes a literal character.

<\/a> interprets the forward slash literally in the end HTML anchor tag.

Precedes an escape sequence.

\n matches a newline character.

^

Matches the beginning of a string, not including the newline character.

^apple matches “apple” at the beginning of a string.

$

Matches the end of a string, not including the newline character.

apple$ matches “apple” at the end of a string.

.

Matches any single character including a newline character.

.apple matches any single character and then “apple”.

|

Represents a logical OR to separate alternative values.

(apple|orange|banana) matches “apple”, “orange”, or “banana”.

?

Matches zero or one instance.

apple (pie)? matches one or more instances of “pie”.

*

Matches zero or more instances.

+

Matches one or more instances.

( )

Encloses a sub-expression.

(apple|orange|banana) matches “apple”, “orange”, or “banana”.

^(\w+) matches the beginning of a line and then one or more word characters.

[ ]

Encloses an expression that matches set of characters.

[\s] matches a whitespace character or a digit.

[a-z0-9] matches “a” through “z” and numbers “0” through “9”.

{ }

Encloses an expression that represents repetition.

apple{3} repeats three times.

apple{3,} repeats at least three times as many times as possible.

apple{3, 10} repeats three times but no more than 10 times.

Append a question mark to indicate repeating as few times as possible. For example, apple{3,}? repeats at least three times as few times as possible.

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