Skip to content

Instantly share code, notes, and snippets.

@pedromancheno

pedromancheno/Swaping (key-value)

Last active December 25, 2015 15:29
Show Gist options
  • Save pedromancheno/6998204 to your computer and use it in GitHub Desktop.
Save pedromancheno/6998204 to your computer and use it in GitHub Desktop.
Download ZIP
Categories for NSDictionary and NSArray for swapping the keys of a dictionary for it's value.
Raw
Swaping (key-value)
@interface NSDictionary (Swapping)
- (NSDictionary *)dictionaryBySwappingKeyWithValue;
@end
@interface NSDictionary (Swapping)
- (NSDictionary *)dictionaryBySwappingKeyWithValue
{
NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithCapacity:self.count];
[self enumerateKeysAndObjectsUsingBlock:^(id key, id value, BOOL *stop) {
id newKey = nil;
if ([value isKindOfClass:[NSDictionary class]]) {
newKey = [value dictionaryBySwappingKeyWithValue];
} else if ([value isKindOfClass:[NSArray class]]) {
newKey = [value arrayBySwappingKeyWithValue];
} else {
newKey = value;
}
if (![newKey conformsToProtocol:@protocol(NSCopying)]) {
newKey = [NSValue valueWithNonretainedObject:newKey];
}
mutableDictionary[newKey] = key;
}];
return [NSDictionary dictionaryWithDictionary:mutableDictionary];
}
@end
@interface NSArray (Swapping)
- (NSArray *)arrayBySwappingKeyWithValue;
@end
@implementation NSArray (Swapping)
- (NSArray *)arrayBySwappingKeyWithValue
{
NSMutableArray *mutableArray = [NSMutableArray arrayWithCapacity:self.count];
[self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
if ([obj isKindOfClass:[NSDictionary class]]) {
NSDictionary *newDict = [obj dictionaryBySwappingKeyWithValue];
mutableArray[idx] = newDict;
} else if ([obj isKindOfClass:[NSArray class]]) {
NSArray *newArray = [obj arrayBySwappingKeyWithValue];
mutableArray[idx] = newArray;
} else {
mutableArray[idx] = obj;
}
}];
return [NSArray arrayWithArray:mutableArray];
}
@end
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment