Special characters with regular expressions and wildcards
A wildcard character is a special character that represents one or more other characters. The most commonly used wildcard characters are the asterisk (
*), which typically represents zero or more characters, and the question mark (
?), which typically represents any one character.
In Perl-style regular expressions, the period (
.) character refers to any single character. It is similar to the question mark (
?) character in wildcard match pattern. As a result, example.com not only matches example.com but also exampleacom, examplebcom, exampleccom, and so forth.
To match a special character such as “
.” and “
*” use the backslash (
\ ) escape character. For example, to match example.com, the regular expression should be:
In Perl regular expressions, an asterisk (
*) matches the character before it 0 or more times, not 0 or more times of any character. For example,
exampleeeeee.com but does not match
To match any character 0 or more times, use “
.*” where “
.” means any character and the “
*” means 0 or more times. For example, the wildcard match pattern
exampl*.com should therefore be
To match any single character within a range of characters, enclose the character-set in square brackets (
[ ]). For example,
[A-Za-z] matches any single uppercase or lowercase letter.