Creates and returns a mutable dictionary, initially giving it enough allocated memory to hold a given number of entries.
- iOS 2.0+
- macOS 10.0+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The initial capacity of the new dictionary.
A new mutable dictionary with enough allocated memory to hold
Mutable dictionaries allocate additional memory as needed, so
num simply establishes the object’s initial capacity.