Question

I am looking for a way to compare two strings and see if the second string contains a character (letter, number, other) listed in the first, let me explain:

For example: Imagine a password with only digits and “*” are allowed:
Reference chain (1): “*0123456789” NSString format, no NSArray
Work chain (2) = “156/15615=211” NSString format,

How do I know that my chain 2 contains 2 characters (/=) which are not in my chain 1?

To simplify the management letters allowed, I do not want to use NSArray to manage a chain for example a function call:

BOOL unauthorized_letter_found = check(work_chain, reference_chain);

You it must go through “for”, NSPredicate, etc. ?

PS: I’m on MAC OS, not iOS so I can not use NSRegularExpression.

Answer 1

If you want to use an NSPredicate, you can do:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES '[0-9*]+'"];
if ([predicate evaluateWithObject:@"0*2481347*"]) {
  NSLog(@"passes!");
} else {
  NSLog(@"fails!");
}

This is using NSPredicate‘s built-in regular expression matching stuff. 🙂