如何将值插入到嵌套的Swift字典中

I'm trying to insert new key-value pair in dictionary, which nested in another one Dictionary:

我想在字典中插入新的键值对，它嵌套在另一个字典中:

var dict = Dictionary<Int, Dictionary<Int, String>>()

dict.updateValue([1 : "one", 2: "two"], forKey: 1)
dict[1]?[1] // {Some "one"}

if var insideDic =  dict[1] {
    // it is a copy, so I can't insert pair this way:
    insideDic[3] = "three"
}

dict // still [1: [1: "one", 2: "two"]]

dict[1]?[3] = "three" // Cannot assign to the result of this expression
dict[1]?.updateValue("three", forKey: 3) // Could not find a member "updateValue"

I believe should be a simple way to handle it, but I spent an hour and still can't figure it out. I can use NSDictionary instead, but I really like to understand how I should manage nested Dictionaries in Swift?

我认为这应该是一个简单的方法来处理它，但我花了一个小时还是搞不清楚。我可以使用NSDictionary，但我真的很想了解如何在Swift中管理嵌套字典?

2 个解决方案

#1

Dictionarys are value types so are copied on assignment. As a result you are going to have to get the inner dictionary (which will be a copy), add the new key, then re-assign.

字典是值类型，所以在分配时被复制。因此，您将不得不获取内部字典(它将是一个副本)，添加新键，然后重新分配。

// get the nested dictionary (which will be a copy)
var inner:Dictionary<Int, String> = dict[1]!

// add the new value
inner[3] = "three"

// update the outer dictionary
dict[1] = inner
println(dict) // [1: [1: one, 2: two, 3: three]]

You could use one of the new utility libraries such as ExSwift to make this a bit simpler:

您可以使用一个新的实用程序库，如ExSwift，使其更简单一点:

dict[1] = dict[1]!.union([3:"three"])

This uses the union method that combines two dictionaries.

这使用了合并两个字典的union方法。

#2

Better declare it as a NSMutableDictionary and you can use setValue(value: , forKeyPath)

最好将它声明为NSMutableDictionary，并使用setValue(value:， forKeyPath)

#1