问题
How can I write a regex that matches only letters?
回答1:
Use a character set: [a-zA-Z] matches one letter from A–Z in lowercase and uppercase. [a-zA-Z]+ matches one or more letters and ^[a-zA-Z]+$ matches only strings that consist of one or more letters only (^ and $ mark the begin and end of a string respectively).
If you want to match other letters than A–Z, you can either add them to the character set: [a-zA-ZäöüßÄÖÜ]. Or you use predefined character classes like the Unicode character property class \p{L} that describes the Unicode characters that are letters.
回答2:
\p{L} matches anything that is a Unicode letter if you're interested in alphabets beyond the Latin one
回答3:
Depending on your meaning of "character":
[A-Za-z]- all letters (uppercase and lowercase)
[^0-9]- all non-digit characters
回答4:
The closest option available is
[\u\l]+
which matches a sequence of uppercase and lowercase letters. However, it is not supported by all editors/languages, so it is probably safer to use
[a-zA-Z]+
as other users suggest
回答5:
You would use
/[a-z]/gi
[]--checks for any characters between given inputs
a-z---covers the entire alphabet
g-----globally throughout the whole string
i-----getting upper and lowercase
回答6:
Regular expression which few people has written as "/^[a-zA-Z]$/i" is not correct because at the last they have mentioned /i which is for case insensitive and after matching for first time it will return back. Instead of /i just use /g which is for global and you also do not have any need to put ^ $ for starting and ending.
/[a-zA-Z]+/g
- [a-z_]+ match a single character present in the list below
- Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed
- a-z a single character in the range between a and z (case sensitive)
- A-Z a single character in the range between A and Z (case sensitive)
- g modifier: global. All matches (don't return on first match)
回答7:
For PHP, following will work fine
'/^[a-zA-Z]+$/'
回答8:
/[a-zA-Z]+/
Super simple example. Regular expressions are extremely easy to find online.
http://www.regular-expressions.info/reference.html
回答9:
Java:
String s= "abcdef";
if(s.matches("[a-zA-Z]+")){
System.out.println("string only contains letters");
}
回答10:
Just use \w or [:alpha:]. It is an escape sequences which matches only symbols which might appear in words.
回答11:
Use character groups
\D
Matches any character except digits 0-9
^\D+$
See example here
回答12:
You can try this regular expression : [^\W\d_] or [a-zA-Z].
回答13:
If you mean any letters in any character encoding, then a good approach might be to delete non-letters like spaces \s, digits \d, and other special characters like:
[!@#\$%\^&\*\(\)\[\]:;'",\. ...more special chars... ]
Or use negation of above negation to directly describe any letters:
\S \D and [^ ..special chars..]
Pros:
- Works with all regex flavors.
- Easy to write, sometimes save lots of time.
Cons:
- Long, sometimes not perfect, but character encoding can be broken as well.
回答14:
pattern = /[a-zA-Z]/
puts "[a-zA-Z]: #{pattern.match("mine blossom")}" OK
puts "[a-zA-Z]: #{pattern.match("456")}"
puts "[a-zA-Z]: #{pattern.match("")}"
puts "[a-zA-Z]: #{pattern.match("#$%^&*")}"
puts "[a-zA-Z]: #{pattern.match("#$%^&*A")}" OK
回答15:
Pattern pattern = Pattern.compile("^[a-zA-Z]+$");
if (pattern.matcher("a").find()) {
...do something ......
}
来源：https://stackoverflow.com/questions/3617797/regex-to-match-only-letters