objective c: if something has something in it - do something

Question

I want to do this:

while(theString (does not have) @"this string" (in it)) {
do something
}

Answer 1

From this stackoverflow post:

NSString *string = @"hello bla bla";
if ([string rangeOfString:@"bla"].location == NSNotFound) {
  NSLog(@"string does not contain bla");
} else {
  NSLog(@"string contains bla!");
}

The key is noticing that rangeOfString: returns an NSRange struct, and the documentation says that it returns the struct {NSNotFound, 0} if the "haystack" does not contain the "needle".