I think you should use updateValue forKey method instead of subscript=value.
Subscript in Dictionary returns an Element?, you should not use it like a
subscript in Array, which returns Element.
Zhaoxin
Get Outlook for iOS
_____________________________
From: Artyom Goncharov via swift-users <swift-users@swift.org>
Sent: 星期三, 五月 18, 2016 6:56 下午
Subject: [swift-users] Dictionary with optional values
To: <swift-users@swift.org>
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
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