Regex only allow letters and some characters

Question

I am attempting to create a regex that only allows letters upper or lowercase, and the characters of space, '-', ',' '.', '(', and ')'. This is what I have so far but for some reason it is still letting me enter numbers

^[a-zA-Z -,.()]*$

any help would be great! Thanks.

Answer 1

- is special in character class. It is used to define a range as you've done with a-z.

To match a literal - you need to either escape it or place it such that it'll not function as range operator:

^[a-zA-Z \-,.()]*$
         ^^ escaping \ 

or

^[-a-zA-Z ,.()]*$
  ^ placing it at the beginning.

or

^[a-zA-Z -,.()-]*$
              ^ placing it at the end.

and interestingly

^[a-z-A-Z -,.()]*$
     ^ placing in the middle of two ranges.

In the final case - is place between a-z and A-Z since both the characters surrounding the -(the one which we want to treat literally) that is z and A are already involved in ranges, the - is treated literally again.

Of all the mentioned methods, the escaping method is recommended as it makes your code easier to read and understand. Anyone seeing the \ would expect that an escape is intended. Placing the - at the beginning(end) will create problems if you later add a character before(after) it in the character class without escaping the - thus forming a range.