Swift1.2数组声明，额外的括号?-Swift1.2Arraydeclaration,extrabrackets?

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There is no difference. The (String) form actually means a tuple with one value of String type, but it's equivalent to just saying a String.

没有区别。(字符串)形式实际上是指有一个字符串类型值的元组，但它等价于只说一个字符串。

For instance, consider the following array:

例如，考虑以下数组:

var array = [String]()

you can append a string element as usual:

您可以像往常一样添加一个字符串元素:

array.append("raw string")

but you can also add a tuple containing one string value:

但也可以添加一个包含一个字符串值的元组:

let tuple = (namedValue: "from tuple")
array.append(tuple)

Note that the equivalence doesn't stop here. If you have a function/method accepting n parameters:

注意，等价性并不仅限于此。如果你有一个接受n个参数的函数/方法:

func aFunc(#param1: Int, #param2: String, #param3: Double) {}

when invoking it you can provide the list of parameters:

当调用它时，您可以提供参数列表:

aFunc(param1: 1, param2: "text", param3: 3.14)

but you can also group the parameters into a tuple, and just it to the function

但是你也可以将参数分组到一个元组中，并将其分组到函数中

let params = (param1: 1, param2: "text", param3: 3.14)
aFunc(params)