Which regular expression can I use to match (allow) any kind of letter from any language?

I need to match any letter including any diacritics (e.g., á, ü, ñ) and exclude any kind of symbol (math symbols, currency signs, dingbats, box-drawing characters, etc.) and punctuation characters.

I'm using ASP.NET MVC 2 with .NET 4. I’ve tried this annotation in my view model

[RegularExpression(@"\p{L}*", ...

and this one

[RegularExpression(@"\p{L}\p{M}*", ...

but client-side validation rejects accented characters.

UPDATE: Thank you for all your answers. Your suggestions work but only for .NET, and the problem here is that it also uses the regex for client-side validation with JavaScript.

I had to go with

[^0-9_\|°¬!#\$%/\\\(\)\?¡¿\+\{\}\[\]:\.\,;@ª^\*<>=&]

which is very ugly and does not cover all scenarios but is the closest thing to what I need.

Which regular expression can I use to match (allow) any kind of letter from any language?

I need to match any letter including any diacritics (e.g., á, ü, ñ) and exclude any kind of symbol (math symbols, currency signs, dingbats, box-drawing characters, etc.) and punctuation characters.

I'm using ASP.NET MVC 2 with .NET 4. I’ve tried this annotation in my view model

[RegularExpression(@"\p{L}*", ...

and this one

[RegularExpression(@"\p{L}\p{M}*", ...

but client-side validation rejects accented characters.

UPDATE: Thank you for all your answers. Your suggestions work but only for .NET, and the problem here is that it also uses the regex for client-side validation with JavaScript.

I had to go with

[^0-9_\|°¬!#\$%/\\\(\)\?¡¿\+\{\}\[\]:\.\,;@ª^\*<>=&]

which is very ugly and does not cover all scenarios but is the closest thing to what I need.

• javascript
• .net
• regex
• unicode
• asp.net-mvc-2

6 Answers 6

You can use Char.IsLetter:

Indicates whether the specified Unicode character is categorized as a Unicode letter.

With .Net 4.0:

string onlyLetters = String.Concat(str.Where(Char.IsLetter));

On 3.5 String.Concat only excepts an array, so you should also call ToArray.

Your problem is more likely to the fact that you will only have to have one alpha-char, because the regex will match anything that has at least one char.

By adding ^ as prefix and $ as postfix, the whole sentence should comply to your regex. So this prob works:

^\p{L}*$

Regexbuddy explains:

1. ^ Assert position at beginning of the string
2. \p{L} A character with the Unicode property 'letter' (any kind of letter from any kind of language) 2a. Between zero and unlimited times, as many as possible (greedy)
3. $ Assert position at the end of the string

\p{L}* should match "any kind of letter from any language". It should work, I used it in a i18n-proof uppercase/lowercase recognition regex in .NET.

I’ve just had to validate a URL and I chose this regular expression in .NET.

^[(\p{L})?(\p{M})?-]*$

Begin and end with a character of any language (optionally either letters or marks) and allow hyphens.

One thing to watch out for is the client-side regex. It uses javascript regex on the client side and .net regex on the server side. Javascript won't support this scenario.

\w - matches any alphanumeric character (including numbers)

In my tests it has matched:

• ã
• à
• ç
• 8
• z

and hasn't matched:

• ;
• ,
• \
• :

In case you know exactly what you want to exclude (like a little list) you cand do the following:

[^;,\`.]

which matches one time any character that isnt:

• ;
• ,
• \
• `
• .

Hope it helps!