比较 Swift 中的两个 [String: Any] 字典 4

Question

我有两个词典用作 [String: Any] 类型的文本属性，为了打开或关闭所需的属性，我需要检查两个词典是否相同。

我尝试了以下方法：

let current = inputTextView.typingAttributes

let undo = current.elementsEqual(attributes, by: { (arg0, arg1) -> Bool in
    return ((arg0.key == arg1.key) && (arg0.value == arg1.value))
})

但是在第二次评估时我得到了错误：

Binary operator '==' cannot be applied to two 'Any' operands

比较两个类型 [String: Any] 的字典的最佳方法是什么？？

谢谢

Answer 1

Any 不符合 Equatable 协议。如果要使用 == 运算符，它是类型的必备条件。因此，您需要使用带有类型参数的函数来比较 Any 对象，如 :

中所述

func isEqual<T: Equatable>(type: T.Type, a: Any, b: Any) -> Bool? {
    guard let a = a as? T, let b = b as? T else { return nil }
    return a == b
}

但是，要使用此函数，您应该知道 typingAttributes 中每个值的确切类型。您可以使用 Mirror 结构实现此目的，如下所示：

let lilAny: Any = "What's my type? :("
print(Mirror(reflecting: lilAny).subjectType) // String

Answer 2

详情

Xcode 版本 10.3 (10G8), Swift 5

解决方案

func areEqual (_ left: Any, _ right: Any) -> Bool {
    if  type(of: left) == type(of: right) &&
        String(describing: left) == String(describing: right) { return true }
    if let left = left as? [Any], let right = right as? [Any] { return left == right }
    if let left = left as? [AnyHashable: Any], let right = right as? [AnyHashable: Any] { return left == right }
    return false
}

extension Array where Element: Any {
    static func != (left: [Element], right: [Element]) -> Bool { return !(left == right) }
    static func == (left: [Element], right: [Element]) -> Bool {
        if left.count != right.count { return false }
        var right = right
        loop: for leftValue in left {
            for (rightIndex, rightValue) in right.enumerated() where areEqual(leftValue, rightValue) {
                right.remove(at: rightIndex)
                continue loop
            }
            return false
        }
        return true
    }
}
extension Dictionary where Value: Any {
    static func != (left: [Key : Value], right: [Key : Value]) -> Bool { return !(left == right) }
    static func == (left: [Key : Value], right: [Key : Value]) -> Bool {
        if left.count != right.count { return false }
        for element in left {
            guard   let rightValue = right[element.key],
                areEqual(rightValue, element.value) else { return false }
        }
        return true
    }
}

用法

let comparisonResult = ["key1": 1, 2: "Value2"] == ["key1": ["key2":2]]     // false
print("!!!! \(comparisonResult)")

一些测试

func test(dict1: [AnyHashable : Any], dict2:  [AnyHashable : Any]) {
    print("========================")
    print("dict1: \(dict1)")
    print("dict2: \(dict2)")
    print("are\(dict1 == dict2 ? " " : " not ")equal")
}

test(dict1: ["key1": 1, 2: "Value2"],
     dict2: ["key1": 1, 2: "Value2"])

test(dict1: ["key1": 1, 2: "Value2"],
     dict2: ["key1": 1])

test(dict1: [2: "Value2"],
     dict2: ["key1": 1])

test(dict1: ["1": 1],
     dict2: [1: 1])

test(dict1: [1: 2],
     dict2: [1: 3])

test(dict1: ["key1": [1,2,3,4]],
     dict2: ["key1": [1,2,3,4]])

test(dict1: ["key1": [1,2,3,4]],
     dict2: ["key1": [2,1,3,4]])

test(dict1: ["key1": [1,2,3,4]],
     dict2: ["key1": [2,1,3]])

test(dict1: ["key1": [1,2,3,4]],
     dict2: ["key1": [1,2,3,"4"]])

test(dict1: ["key1": ["key2":2]],
     dict2: ["key1": ["key2":2]])

test(dict1: ["key1": ["key2":2]],
     dict2: ["key1": ["key2":3]])

test(dict1: ["key1": ["key2":2]],
     dict2: ["key1": ["key2":3]])

测试结果

========================
dict1: [AnyHashable("key1"): 1, AnyHashable(2): "Value2"]
dict2: [AnyHashable("key1"): 1, AnyHashable(2): "Value2"]
are equal
========================
dict1: [AnyHashable("key1"): 1, AnyHashable(2): "Value2"]
dict2: [AnyHashable("key1"): 1]
are not equal
========================
dict1: [AnyHashable(2): "Value2"]
dict2: [AnyHashable("key1"): 1]
are not equal
========================
dict1: [AnyHashable("1"): 1]
dict2: [AnyHashable(1): 1]
are not equal
========================
dict1: [AnyHashable(1): 2]
dict2: [AnyHashable(1): 3]
are not equal
========================
dict1: [AnyHashable("key1"): [1, 2, 3, 4]]
dict2: [AnyHashable("key1"): [1, 2, 3, 4]]
are equal
========================
dict1: [AnyHashable("key1"): [1, 2, 3, 4]]
dict2: [AnyHashable("key1"): [2, 1, 3, 4]]
are equal
========================
dict1: [AnyHashable("key1"): [1, 2, 3, 4]]
dict2: [AnyHashable("key1"): [2, 1, 3]]
are not equal
========================
dict1: [AnyHashable("key1"): [1, 2, 3, 4]]
dict2: [AnyHashable("key1"): [1, 2, 3, "4"]]
are not equal
========================
dict1: [AnyHashable("key1"): ["key2": 2]]
dict2: [AnyHashable("key1"): ["key2": 2]]
are equal
========================
dict1: [AnyHashable("key1"): ["key2": 2]]
dict2: [AnyHashable("key1"): ["key2": 3]]
are not equal
========================
dict1: [AnyHashable("key1"): ["key2": 2]]
dict2: [AnyHashable("key1"): ["key2": 3]]
are not equal

比较 Swift 中的两个 [String: Any] 字典 4

Comparing two [String: Any] dictionaries in Swift 4

nsdictionary

ios

swift4

详情

解决方案

用法

一些测试

测试结果