NSDictionary Key exists but returns nil

Question

I have a dictionary which does contain an object but is returns nil.

// returns nil
(lldb) po [_contentRatings objectForKey:rating]
nil
// this is the rating string
(lldb) po rating
'=7+’
// using a literal string works
(lldb) po [_contentRatings objectForKey:@"'=7+'"]
5

It must be not liking the quotes since this fails string equality:

(lldb) po @"'=7+'"
'=7+'
(lldb) po rating
'=7+’
(lldb) p (BOOL)[@"'=7+'" isEqualToString:rating]
(BOOL) $10 = NO

Answer 1

' （ unicode ：撇号）标记与' （ unicode ：右单引号）不同，因此'=7+'不等于'=7+' （请注意最后一个字符）