Get all keys of a multidimensional dictionary - objective-c

Question

I have a dictionary like:
{
dataTypes = (
{
dataType = "datatype1";
editable = 1;
maxValue = 300;
minValue = 0;
order = 1;
title = "Title 1";
type = numeric;
units = kg;
},
{
dataType = "datatype 2";
editable = 1;
maxValue = 300;
minValue = 0;
order = 2;
title = "title2";
type = numeric;
units = gm;
},
{
dataType = "datatype3";
editable = 1;
maxValue = 300;
minValue = 20;
order = 3;
title = "title3";
type = numeric;
units = kg;
}
);
name = "Name";
order = 1
title = "Title";
}
I want to get all keys within this dictionary.
I tried [myDict allKeys], however this is returning only four keys: DataTypes, name, order, title.
I want to retrieve all keys: dataType, editable, maxvalue, etc.

Answer 1

Try this.
NSArray *tempArray = [myDict objectForKey:#"dataTypes"];
NSDictionary *tempDictionary = (NSDictionary *)tempArray[0];
[tempDictionary allKeys] will have what you want.
Write this method.
- (NSDictionary *)dictionaryFromArrayWithinDictionary:(NSDictionary *)dictionary withKey:(NSString *)key{
NSArray *tempArray = [dictionary objectForKey:key];
return (NSDictionary *)tempArray[0];
}
This will return the inner dictionary and simply calling `allKeys' on this dictionary, you will get all the keys you want.

Answer 2

You need to recursively walk through your dictionary, and through any arrays the dictionary might contain, and so on. This can be nicely done via a recursiveKeys method added to all objects, which returns an empty array for objects that are not containers, and walks though the container for objects that are containers:
#interface NSObject(MyCategory)
- (NSArray)recursiveKeys;
#end
#implementation NSObject(MyCategory)
- (NSArray)recursiveKeys {
return #[];
}
#end
#implementation NSArrray(MyCategory)
- (NSArray)recursiveKeys {
NSMutableArray *result = [NSMutableArray array];
for (id item in self) {
[result addObjectsFromArray:[item recursiveKeys]];
}
return [result copy]; //return an immutable array
}
#end
#implementation NSSet(MyCategory)
- (NSArray)recursiveKeys {
NSMutableArray *result = [NSMutableArray array];
for (id item in self) {
[result addObjectsFromArray:[item recursiveKeys]];
}
return [result copy]; //return an immutable array
}
#end
#implementation NSDictionary(MyCategory)
- (NSArray)recursiveKeys {
NSMutableArray *result = [self.allKeys mutableCopy];
for (id key in self) {
[result addObjectsFromArray:[self[key] recursiveKeys];
}
return [result copy]; //return an immutable array
}
#end
You can use it like this:
NSArray *keys = myDictionary.recursiveKeys;
Please pardon any syntax errors, I don't have at this time an Xcode in front of me, I simply typed the code here on SO.