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What is word boundary in regular expression?
Answer

Wiki User
April 04, 2008 6:22AM
word boundary '/b' is any character other than alphanumeric and underscore ie. [^A-Za-z0-9_]
Related Questions
Asked in PHP Programming, Computer Programming
What is a regular expression?

In programming, a regular expression is an expression that
explains a pattern for a string. A string matches a regular
expression if that string follows the pattern of that regular
expression. For example, you may want to create an account system,
allowing usernames to only have uppercase and lowercase letters,
and numbers. While a user is registering, you can check their
desired username against a regular expression involving only
alphanumeric characters (A-Z, a-z, 0-9). If it matches, then the
username is valid to your requests. If it does not, the user has
put in a character that does not follow the pattern of the regular
expression. In regular expressions, you can match certain
characters, match a certain quanity of characters, match the casing
of characters (or just ignore it overall), and plenty more. The
syntax of a regular expression varies throughout every programming
language, but Perl is often used due to its wide variety of
options. Perl is also incorporated into many web languages, such as
PHP, making regular expressions less of a hassle. This is an
example of a Perl regular expression, allowing a string with only
alphanumeric characters (any character case), and an infinite
length (except for a string with no length or no characters, in
which the regular expression does not match the string):
/^(?i)[a-z0-9]+$/