I have this regex ^[A-ZÆØÅa-zæøå\ \-]{2,50}$ for validating names. How can I make it allow only one "-". I want it to accept names like this:
Janet Smith-Johnson
Mary-Ann Johnson
Sara Mary John-Smith
Sara Johnson
Sara Mary Johnson
But it can't allow names that starts with - and ends with -. Like:
-Janet Mary
Mary-
You can match your character class without spaces, then optionally repeat a space and again use the character class without spaces.
Then optionally match - and the same mechanism again.
^(?=.{2,50}$)[A-ZÆØÅa-zæøå]+(?: [A-ZÆØÅa-zæøå]+)*(?:-[A-ZÆØÅa-zæøå]+(?: [A-ZÆØÅa-zæøå]+)*)?$
The pattern in parts matches:
^ Start of string(?=.{2,50}$) Assert 2 - 50 characters[A-ZÆØÅa-zæøå]+ Match what is listed in the character class without a space(?: [A-ZÆØÅa-zæøå]+)* Optionally repeat the character class preceded by a space(?: Non capture group to match as a whole
-[A-ZÆØÅa-zæøå]+ Match what is listed in the character class without a space(?: [A-ZÆØÅa-zæøå]+)* Optionally repeat the character class preceded by a space)? Close the non capture group and make it optional$ End of stringYou can use
^(?=.{2,50}$)(?!(?:.*-){2})[A-ZÆØÅa-zæøå]+(?:[- ][A-ZÆØÅa-zæøå]+)*$
See the regex demo.
If you are using the regex in C# or with u flag in JavaScript that supports ECMAScript 2018+ standard, you can also match any Unicode letter with \p{L}:
^(?=.{2,50}$)(?!(?:.*-){2})\p{L}+(?:[- ]\p{L}+)*$
Details:
^ - start of string(?=.{2,50}$) - two to fifty chars in the string allowed(?!(?:.*-){2}) (or (?!(?:[^-]*-){2}) in the real code is more efficient) - no two hyphens are allowed[A-ZÆØÅa-zæøå]+ - one or more letters from the set (\p{L} matches any Unicode letter)(?:[- ][A-ZÆØÅa-zæøå]+)* - zero or more sequences of either space or - and then one or more letters$ - end of string.