Question

I have an NSArray of strings that I want to use as my sort order:

NSArray *permissionTypes = [NSArray arrayWithObjects:@"Read", @"Write", @"Admin", nil];

I then have a NSMutableArray that may or may not have all three of those permissions types, but sometimes it will only be 2, sometimes 1, but I still want it sorted based on my permissionsTypes array.

NSMutableArray *order = [NSMutableArray arrayWithArray:[permissions allKeys]];

How can I always sort my order array correctly based on my using the permissionTypes array as a key?

Answer 1

I would go about this by creating a struct or an object to hold the permission types.

Then you can have…

PermissionType
--------------
Name: Read
Order: 1

PermissionType
--------------
Name: Write
Order: 2

and so on.

Then you only need the actual array of these objects and you can sort by the order value.

[array sortUsingComparator:^NSComparisonResult(PermissionType *obj1, PermissionType *obj2) {
        return [obj1.order compare:obj2.order];
    }];

This will order the array by the order field.