转载自：http://www.regexlib.com/cheatsheet.htm?AspxAutoDetectCookieSupport=1
Metacharacters Defined
|
|---|
| MChar | Definition |
|---|
| ^ |
Start of a string. |
| $ |
End of a string. |
| . |
Any character (except
newline) |
| | |
Alternation. |
| {...} |
Explicit quantifier notation. |
| [...] |
Explicit set of characters to match. |
| (...) |
Logical grouping of part of an expression. |
| * |
0 or more of previous expression. |
| + |
1 or more of previous expression. |
| ? |
0 or 1 of previous expression; also forces minimal matching when an expression might match several strings within a search string. |
|
Preceding one of the above, it makes it a literal instead of a special character. Preceding a special matching character, see below. |
Metacharacter Examples
|
|---|
| Pattern | Sample Matches |
|---|
| ^abc |
abc, abcdefg, abc123, ... |
| abc$ |
abc, endsinabc, 123abc, ... |
| a.c |
abc, aac, acc, adc, aec, ... |
| bill|ted |
ted, bill |
| ab{2}c |
abbc |
| a[bB]c |
abc, aBc |
| (abc){2} |
abcabc |
| ab*c |
ac, abc, abbc, abbbc, ... |
| ab+c |
abc, abbc, abbbc, ... |
| ab?c |
ac, abc |
| asc |
a c |
|
|
|---|
| Escaped Char | Description |
|---|
| ordinary characters |
Characters other than . $ ^ { [ ( | ) ] } * + ? match themselves. |
| a |
Matches a bell (alarm) u0007. |
|
Matches a backspace u0008 if in a []; otherwise matches a word boundary (between w and W characters). |
| |
Matches a tab u0009. |
|
|
Matches a carriage return u000D. |
| v |
Matches a vertical tab u000B. |
| f |
Matches a form feed u000C. |
|
|
Matches a new line u000A. |
| e |
Matches an escape u001B. |
| 40 |
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 40 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 a hexadecimal representation (exactly four digits). |
| * |
When followed by a character that is not recognized as an escaped character, matches that character. For example, * is the same as x2A. |
|
|
|---|
| Char Class | Description |
|---|
| . |
Matches any character except
. If modified by the Singleline option, a period character matches any character. For more information, see Regular Expression Options. |
| [aeiou] |
Matches any single character included in the specified set of characters. |
| [^aeiou] |
Matches any single character not in the specified set of characters. |
| [0-9a-fA-F] |
Use of a hyphen (–) allows specification of contiguous character ranges. |
| p{name} |
Matches any character in the named character class specified by {name}. Supported names are Unicode groups and block ranges. For example, Ll, Nd, Z, IsGreek, IsBoxDrawing. |
| P{name} |
Matches text not included in groups and block ranges specified in {name}. |
| w |
Matches any word character. Equivalent to the Unicode character categories [p{Ll}p{Lu}p{Lt}p{Lo}p{Nd}p{Pc}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, w is equivalent to [a-zA-Z_0-9]. |
| W |
Matches any nonword character. Equivalent to the Unicode categories [^p{Ll}p{Lu}p{Lt}p{Lo}p{Nd}p{Pc}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, W is equivalent to [^a-zA-Z_0-9]. |
| s |
Matches any white-space character. Equivalent to the Unicode character categories [f
vx85p{Z}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, s is equivalent to [ f
v]. |
| S |
Matches any non-white-space character. Equivalent to the Unicode character categories [^f
vx85p{Z}]. If ECMAScript-compliant behavior is specified with the ECMAScript option, S is equivalent to [^ f
v]. |
| d |
Matches any decimal digit. Equivalent to p{Nd} for Unicode and [0-9] for non-Unicode, ECMAScript behavior. |
| D |
Matches any nondigit. Equivalent to P{Nd} for Unicode and [^0-9] for non-Unicode, ECMAScript behavior. |