出处：regexlib.com regular expression cheat sheet (.net)
元字符
说明
^
匹配字符串...
出处：regexlib.com regular expression cheat sheet (.net)
| 元字符 |
说明 |
| ^ |
匹配字符串的开始位置 |
| $ |
匹配字符串的结束位置 |
| . |
匹配任意单个字符（换行符 \n 除外） |
| | |
交替 |
| {…} |
指定要限定的数量 |
| [...] |
指定要匹配的字符集 |
| (…) |
对表达式进行逻辑分组 |
| * |
匹配零或多个前面的表达式 |
| + |
匹配一或多个前面的表达式 |
| ? |
匹配零或一个前面的表达式 |
| \ |
放在上面任何一个字符之前，表示匹配该字符本身。放在其他特殊字符后面，表示字符转义（见下面） |
| 字符转义 |
说明 |
| 原始字符 |
除 . $ ^ { [ ( | ) ] } * + ? \ 之外的字符均匹配自身 |
| \a |
匹配铃声（闹铃）\u0007 |
| \b |
在[]中匹配一个空格 \u0008，在其他情况下匹配字边界（位于 \w 和 \w 字符之间） |
| \t |
匹配制表符 \u0009 |
| \r |
匹制回车符 \u000d |
| \v |
匹配垂直制表符 \u000b |
| \f |
匹配换页符 \u000c |
| \n |
匹配换行符 \u000a |
| \e |
匹配退出键（符） \u001b |
| \040 |
匹配以八进制表示的 ascii 字符（最多三位数）；在没有前导零的情况下，如果只有一位数字或者相应数字与某个捕获组的编号对应，那就是反向引用（backreference）。字符 \040 表示一个空格。 |
| \x20 |
匹配以十六进制表示的 ascii 字符（两位数） |
| \cc |
匹配 ascii 控制符，例如 \cc 匹配 ctrl+c |
| \u0020 |
匹配以十六进制表示的 unicode 字符 |
| \* |
反斜杠后面如果不是一个可转义的字符，则匹配该字符本身。例如，\* 就相当于\x2a |
| 字符类 |
说明 |
| . |
匹配除 \n 之外的任意字符。 |
| [aeiou] |
匹配特定字符集中包含的任意一个字符 |
| [^aeiou] |
匹配特定字符集中不包含的任意一个字符 |
| [0-9a-fa-f] |
连字符（-）用来指定连续的字符范围 |
| \p{name} |
匹配由{name}指定的命名字符类中的任意字符 |
| \p{name} |
匹配不包含在{name}指定的组或块范围中的文本 |
| \w |
匹配英文数字字母字符，在指定兼容ecmascript的情况下，等价于[a-za-z0-9] |
| \w |
匹配非英文数字字母字符，在指定兼容ecmascript的情况下，等价于[^a-za-z0-9] |
| \s |
匹配任意空白字符，在指定兼容ecmascript的情况下，等价于[\f\n\r\t\v] |
| \s |
匹配任意非空白字符，在指定兼容ecmascript的情况下，等价于[^\f\n\r\t\v] |
| \d |
匹配数字字符，在指定兼容ecmascript的情况下，等价于[0-9] |
| \d |
匹配非数字字符，在指定兼容ecmascript的情况下，等价于[^0-9] |
英文版:
metacharacters defined
|
|---|
| mchar |
definition |
| ^ |
start of a string. |
| $ |
end of a string. |
| . |
any character (except \n 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 |
| a\sc |
a c |
character escapes http://tinyurl.com/5wm3wl
|
|---|
| escaped char |
description |
| ordinary characters |
characters other than . $ ^ { [ ( | ) ] } * + ? \ match themselves. |
| \a |
matches a bell (alarm) \u0007. |
| \b |
matches a backspace \u0008 if in a []; otherwise matches a word boundary (between \w and \w characters). |
| \t |
matches a tab \u0009. |
| \r |
matches a carriage return \u000d. |
| \v |
matches a vertical tab \u000b. |
| \f |
matches a form feed \u000c. |
| \n |
matches a new line \u000a. |
| \e |
matches an escape \u001b. |
| \040 |
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 \040 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. |
character classes http://tinyurl.com/5ck4ll
|
|---|
| char class |
description |
| . |
matches any character except \n. 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\n\r\t\v\x85\p{z}]. if ecmascript-compliant behavior is specified with the ecmascript option, \s is equivalent to [ \f\n\r\t\v]. |
| \s |
matches any non-white-space character. equivalent to the unicode character categories [^\f\n\r\t\v\x85\p{z}]. if ecmascript-compliant behavior is specified with the ecmascript option, \s is equivalent to [^ \f\n\r\t\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. |