Dictionary (key , value) order

Question

Assume i have the following code

var dictionary = [\"cat\": 2,\"dog\":4,\"snake\":8]; // mutable dictionary
var keys  = dictionary.keys
var values = dictionary.         


        

Answer 1

No, it is not guaranteed to be in the same order. From documentation:

Swift’s Dictionary type is an unordered collection. The order in which keys, values, and key-value pairs are retrieved when iterating over a dictionary is not specified.

Answer 2

The definition of the keys and values property is preceded by the following comments:

/// A collection containing just the keys of `self`
///
/// Keys appear in the same order as they occur as the `.0` member
/// of key-value pairs in `self`.  Each key in the result has a
/// unique value.
var keys: LazyBidirectionalCollection<MapCollectionView<[Key : Value], Key>> { get }

/// A collection containing just the values of `self`
///
/// Values appear in the same order as they occur as the `.1` member
/// of key-value pairs in `self`.
var values: LazyBidirectionalCollection<MapCollectionView<[Key : Value], Value>> { get }

My interpretation of

Keys/Values appear in the same order as they occur as the .0/.1 member of key-value pairs in self.

is that dictionary.keys and dictionary.values return the keys and values in "matching" order.

So the key-value pairs of a dictionary do not have a specified order, but the first, second, ... element of dictionary.values is the dictionary value corresponding to the first, second, ... element of dictionary.keys.