Question

I need to remove/replace all characters except for alpha numeric, -, & from NSString. How do i construct my regular expression to achieve that
I want to ensure user does not enter any characters other than alphanumeric, & and – in uitextfield. How can i do that. Previusly i Handled things in shoulchangecharactersineange, but now the filter is getting increasigly big to handle through if conditions. Regular expressions may be the best choice for my scenario. I’d apprecite your thoughts and inputs

Answer 1

-(BOOL)textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)r replacementString:(NSString*)s
{
  NSCharacterSet * reject = [[NSCharacterSet characterSetWithCharactersInString:@"QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm1234567890-&"] invertedSet];
  if ([s rangeOfCharacterFromSet:reject].length)
  {
    return NO;
  }
  return YES;
}