Regex for names
While I agree with the answers saying you basically can't do this with regex, I will point out that some of the objections (internationalized characters) can be resolved by using UTF strings and the \p{L} character class (matches a unicode "letter").
- Hyphenated Names (Worthington-Smythe)
Add a - into the second character class. The easiest way to do that is to add it at the start so that it can't possibly be interpreted as a range modifier (as in a-z).
^[A-Z][-a-zA-Z]+$
- Names with Apostophies (D'Angelo)
A naive way of doing this would be as above, giving:
^[A-Z][-'a-zA-Z]+$
Don't forget you may need to escape it inside the string! A 'better' way, given your example might be:
^[A-Z]'?[-a-zA-Z]+$
Which will allow a possible single apostrophe in the second position.
- Names with Spaces (Van der Humpton) - capitals in the middle which may or may not be required is way beyond my interest at this stage.
Here I'd be tempted to just do our naive way again:
^[A-Z]'?[- a-zA-Z]+$
A potentially better way might be:
^[A-Z]'?[- a-zA-Z]( [a-zA-Z])*$
Which looks for extra words at the end. This probably isn't a good idea if you're trying to match names in a body of extra text, but then again, the original wouldn't have done that well either.
- Joint Names (Ben & Jerry)
At this point you're not looking at single names anymore?
Anyway, as you can see, regexes have a habit of growing very quickly...
THE BEST REGEX EXPRESSIONS FOR NAMES:
- I will use the term special character to refer to the following three characters:
- Dash -
- Hyphen '
- Dot .
- Spaces and special characters can not appear twice in a row (e.g.: -- or '. or .. )
- Trimmed (No spaces before or after)
- You're welcome ;)
Mandatory single name, WITHOUT spaces, WITHOUT special characters:
^([A-Za-z])+$
- Sierra is valid, Jack Alexander is invalid (has a space), O'Neil is invalid (has a special character)
Mandatory single name, WITHOUT spaces, WITH special characters:
^[A-Za-z]+(((\'|\-|\.)?([A-Za-z])+))?$
- Sierra is valid, O'Neil is valid, Jack Alexander is invalid (has a space)
Mandatory single name, optional additional names, WITH spaces, WITH special characters:
^[A-Za-z]+((\s)?((\'|\-|\.)?([A-Za-z])+))*$
- Jack Alexander is valid, Sierra O'Neil is valid
Mandatory single name, optional additional names, WITH spaces, WITHOUT special characters:
^[A-Za-z]+((\s)?([A-Za-z])+)*$
- Jack Alexander is valid, Sierra O'Neil is invalid (has a special character)
SPECIAL CASE
Many modern smart devices add spaces at the end of each word, so in my applications I allow unlimited number of spaces before and after the string, then I trim it in the code behind. So I use the following:
Mandatory single name + optional additional names + spaces + special characters:
^(\s)*[A-Za-z]+((\s)?((\'|\-|\.)?([A-Za-z])+))*(\s)*$
Add your own special characters
If you wish to add your own special characters, let's say an underscore _ this is the group you need to update:
(\'|\-|\.)
To
(\'|\-|\.|\_)
PS: If you have questions comment here and I will receive an email and respond ;)
This regex is perfect for me.
^([ \u00c0-\u01ffa-zA-Z'\-])+$
It works fine in php environments using preg_match(), but doesn't work everywhere.
It matches Jérémie O'Co-nor so I think it matches all UTF-8 names.