Question

I want to create an enum-like set of strings in a way that will also provide me the ability to order them by their ordinal value and NOT by alphabetic value. for example:

“Extremely Low” = 0

“Very Low” = 1

“Low” = 2

“Medium = 3

“High” = 4

and so on.

I know that in Java and C# for example, enum types can have a value besides their ordinal value.

Is there any way to achieve the same goal in Objective-C?

Thanks!

Answer 1

Just keep the strings for I/O and use an enum for all your computations. For example, define your enum:

typedef enum { ExtremelyLow, VeryLow, ... High } Rating;

You can use this enum in switch statements etc. Now you can use an NSArray or just a simple C-array to map from enum literals to strings:

NSString *RatingToString[] = { @"Extremely Low", @"Very Low", ..., @"High" };

Rating myRating;
NSString *strMyRating = RatingToString[myRating];

Going from the string version to the enum is more involved, you can use the same RatingToString array and do appropriate comparisons (case-insensitive maybe, fuzzy etc.). You could also use an NSDictionary:

NSDictionary StringToRating = [NSDictionary dictionaryWithObjectsAndKeys: RatingToString[ExtremelyLow], [NSNumber numberWithInt:ExtremelyLow, ..., nil];

Now a lookup will do an exact match on your string and return a Rating wrapped as an NSNumber.