[swift-users] Dictionary with optional values

[Artyom Goncharov]

Hi, here is the playground snippet:

var noOptDict = ["one": 1, "two": 2, "three": 3 ]
noOptDict["one"] = nil
noOptDict // “one” is gone

var optDict: [String: Int?] = ["one": 1, "two": 2, "three": nil]
optDict["one"] = nil
optDict // “one” is gone but “three” is still there

So the first dict instance works as it should, the second using opt values allows to store nil but deletes the key when you assign nil. Is it bug, feature, or both?

Best wishes,
Artyom