Question

I’m trying to remove strings with unrecognized characters from string collection. What is the best way to accomplish this?

Answer 1

To remove strings that contain any characters you don’t recognize:
(EG: if you want to accept lowercase letters, then “foo@bar” would be rejected”)

1. Create a regular expression which defines the set of “recognized” characters, and starts with ^ and ends with $. For example, if your “recognized” characters are uppercase A through Z, it would be ^[A-Z]$
2. Reject strings that don’t match

Note: This won’t work for strings that contain newlines, but you can tweak it if you need to support that

To remove strings that contain entirely characters you don’t recognize:
(EG: If you want to accept lowercase letters, then “foo@bar” would be accepted because it does contain at least one lowercase letter)

1. Create a regular expression which defines the set of “recognized” characters, but with a ^ character inside the square brackets, and starts with ^ and ends with $. For example, if your “recognized” characters are uppercase A through Z, it would be ^[^A-Z]$
2. Reject strings that DO match