What are the metacharacters used in a Regular Expression?
Metacharacter | Description |
\ | Specifies the next character as either a special character, a literal, a back reference, or an octal escape. |
^ | Matches the position at the beginning of the input string. |
$ | Matches the position at the end of the input string. |
* | Matches the preceding subexpression zero or more times. |
+ | Matches the preceding subexpression one or more times. |
? | Matches the preceding subexpression zero or one time. |
{n} | Matches exactly n times, where n is a non-negative integer. |
{n,} | Matches at least n times, n is a non-negative integer. |
{n,m} | Matches at least n and at most m times, where m and n are non-negative integers and n <= m. |
. | Matches any single character except "n". |
[xyz] | A character set. Matches any one of the enclosed characters. |
x|y | Matches either x or y. |
[^xyz] | A negative character set. Matches any character not enclosed. |
[a-z] | A range of characters. Matches any character in the specified range. |
[^a-z] | A negative range characters. Matches any character not in the specified range. |
b | Matches a word boundary, that is, the position between a word and a space. |
B | Matches a nonword boundary. 'erB' matches the 'er' in "verb" but not the 'er' in "never". |
d | Matches a digit character. |
D | Matches a non-digit character. |
f | Matches a form-feed character. |
n | Matches a newline character. |
r | Matches a carriage return character. |
s | Matches any whitespace character including space, tab, form-feed, etc. |
S | Matches any non-whitespace character. |
t | Matches a tab character. |
v | Matches a vertical tab character. |
w | Matches any word character including underscore. |
W | Matches any non-word character. |
un | Matches n, where n is a Unicode character expressed as four hexadecimal digits. For example, u00A9 matches the copyright symbol |