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转载 作者:搜寻专家 更新时间:2023-10-31 22:03:59 24 4
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谁能给我解释一下下面的代码(出现在 Apple 的 Swift 书的第 11 页):

var optionalString: String? = "Hello"
optionalString = nil

var optionalName: String? = "Einav Sitton"
var greeting = "HELLO!"

if let name = optionalName {
greeting = "Hello, \(name)"
}

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