Setting nested NSDictionary and NSArray values

Question

I need to be able to be able to set the values of nested NSDictionary and NSArray. For example:

dictionary array dictionary key1 value1

What is the easiest way to get to key1 and set value1? setValueForKeyPath obviously doesn't work with and array.

Answer 1

Using Objective-C's Object Subscripting.

Imagine the following nested dictionaries and arrays:

dictionaryA => arrayB => dictionaryC

• arrayB is stored under @"arrayKey" in dictionaryA, and dictionaryC is stored at index dictionary_index into arrayB.
• dictionaryC should be set to value1 for @"key1";

To set key1, you need to do:

(NSDictionary*)((NSArray*)(dictionaryA[@"arrayKey"])[dictionary_index])[@"key1"] = value1;

See the section Object Subscripting in Clang 3.3 documentation: OBJECTIVE-C LITERALS for more informations.