Question

What I am trying to do: this regex should have to force the first character to be a letter, after that character, letters, a whitespaces or ‘-‘ can be inserted.

This first part works just fine: (^[A-Za-z][A-Za-z -]*$)

Then I would like to allow an empty string as well : (^$)

When I combine the two however, the user can start the string with a whitespace. What am I doing wrong here?
Thanx!

(^[A-Za-z][A-Za-z -]*$)||(^$)

(I don’t know if this info is needed but I use this in Java, as part of a class that extends from InputVerifier, to set verifiers on JTextFields)

Answer 1

The following should do it:

^([A-Za-z][A-Za-z -]*)?$

The ? makes the expression inside the parentheses optional.

The reason your original regex isn’t quite right is the ||. The regex “or” operator is a single |. Now consider x||y. This matches x or an empty string or y. Since the empty string isn’t in any way anchored, Pattern.find() will find at least one instance of it in any input.