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这是我的代码:为什么递增值显示我“()”?
var pictureVersion = snapshotValuesOnline?["PictureVersion"] as! String
print("downloaded: \(pictureVersion)")
var pictureVersionInt = Int(pictureVersion)!
print("toInt : \(pictureVersionInt)")
var pictureInt = pictureVersionInt += 1
print("plusOne : \(pictureInt)")
var pictureIntToString = "\(pictureInt)"
print("toString : \(pictureIntToString)")
这是我的输出:
downloaded: 3
toInt : 3
plusOne :()
toString :()
我在做什么错在这里?
'pictureInt'是'Void',因为'+ ='是一个'inout'函数修改'pictureVersionInt'。 – JAL
为什么你使用'+ ='?为什么不简单'让pictureInt = pictureVersionInt + 1'? –