I've got a layered NSMutableDictionary object and i'd like to be able to remove dictionaries deeper down in the hierarchy. Is there a quick and easy way to do this, for example, a removeObjectAtKeyPath-like method? Can't seem to find one.
Thanks!
Nothing built in, but your basic category method will do just fine:
@implementation NSMutableDictionary (WSSNestedMutableDictionaries)
- (void)WSSRemoveObjectForKeyPath: (NSString *)keyPath
{
// Separate the key path
NSArray * keyPathElements = [keyPath componentsSeparatedByString:@"."];
// Drop the last element and rejoin the path
NSUInteger numElements = [keyPathElements count];
NSString * keyPathHead = [[keyPathElements subarrayWithRange:(NSRange){0, numElements - 1}] componentsJoinedByString:@"."];
// Get the mutable dictionary represented by the path minus that last element
NSMutableDictionary * tailContainer = [self valueForKeyPath:keyPathHead];
// Remove the object represented by the last element
[tailContainer removeObjectForKey:[keyPathElements lastObject]];
}
@end
N.B. That this requires that the second-to-last element of the path -- the tailContainer
be something that responds to removeObjectForKey:
, probably another NSMutableDictionary
. If it's not, boom!