Changing value in nested dictionary in swift

Question

I am wondering why when setting the value of a nested dictionary, the containing dictionary does not reflect those changes? On line3, is a copy of the dictionary being retur

Answer 1

It's because dictionaries are value types and not reference types in Swift.

When you call this line...

var dic2 = dic["key"] as Dictionary

... you are creating an entirely new dictionary, not a reference to the value in dic. Changes in dic2 will not be reflected in dic, because dic2 is now a second entirely separate dictionary. If you want dic to reflect the changes that you made, you need to reassign the value to the appropriate key in dic, like this:

dic["key"] = dic2

Hope that helps...