字典比较数组 - swift 3答案

【问题标题】：Array of dictionary comparision - swift3字典比较数组 - swift 3
【发布时间】：2018-08-15 23:31:08
【问题描述】：

我有 2 个字典数组。我想写一个比较这两个数组的函数。仅当主数组包含子数组元素时，函数才应返回 true。否则它应该返回 false。

这是我的逻辑-

let mainArry = [ ["id":"1","products":["pid": 1, "name": "A", "price": "$5"]], ["id":"3","products":["pid": 3, "name": "B", "price": "$1"]], ["id":"2","products":["pid": 14, "name": "C", "price": "$15"]]]

let array1 = [ ["id":"1","products":["pid": 1, "name": "A", "price": "$5"]], ["id":"3","products":["pid": 3, "name": "B", "price": "$1"]]]

let array2 =  [ ["id":"1","products":["pid": 1, "name": "A", "price": "$5"]], ["id":"3","products":["pid": 4, "name": "B", "price": "$1"]]]

func compareDictionary(mainArry:[[String: Any]], arr2: [[String: Any]])-> Bool{
    let itemsId = arr2.map { $0["id"]! } // 1, 3, 14

    let filterPredicate = NSPredicate(format: "id IN %@", itemsId)

    let filteredArray = mainArry.filter{filterPredicate.evaluate(with:$0) }

    if filteredArray.count != arr2.count {
        return false
    }
    for obj in filteredArray {
        let prd = obj as Dictionary<String, Any>
        let str = prd["id"] as! String
        let searchPredicate = NSPredicate(format: "id == %@", str )

        let filteredArr = arr2.filter{searchPredicate.evaluate(with:$0) }

        if filteredArr.isEmpty {
            return false
        }

        if !NSDictionary(dictionary: obj["products"] as! Dictionary<String, Any>).isEqual(to: filteredArr.last!["products"] as! [String : Any]) {
            return false
        }

    }
    return true

}

let result1 = compareDictionary(mainArry: mainArry, arr2: array1)
let result2 = compareDictionary(mainArry: mainArry, arr2: array2)

print("Result1 = \(result1)")  // true
print("Result2 = \(result2)")  //false

它正在工作。但我想知道实现这一目标的最佳方法。

而不是使用 for-loop 进行比较。我想使用这样的过滤器

let arrayC = filteredArray.filter{
        let dict = $0
        return !arr2.contains{ dict == $0 }
    }

如果 arrayC 为空，则表示两个数组相等。

【问题讨论】：

代码审查 StackExchange 站点是解决有关代码正常工作问题的更好地方。
我强烈建议将字典解析为更强类型的结构或类，然后让这些对象符合 Equatable。
这里无法直接使用过滤功能进行对比。

标签： ios arrays dictionary predicate swift3.2

【解决方案1】：

我终于明白了！我们不需要编写大函数。

let mainArry = [ ["id":"1","products":["pid": 1, "name": "A", "price": "$5"]], ["id":"3","products":["pid": 3, "name": "B", "price": "$1"]], ["id":"2","products":["pid": 14, "name": "C", "price": "$15"]]]

let array1 = [ ["id":"1","products":["pid": 1, "name": "A", "price": "$5"]], ["id":"3","products":["pid": 3, "name": "B", "price": "$1"]]]

let array2 =  [ ["id":"1","products":["pid": 1, "name": "A", "price": "$5"]], ["id":"3","products":["pid": 4, "name": "B", "price": "$1"]]]

let result = array2.filter{
    let dict = $0
    return !mainArry.contains{
        return NSDictionary(dictionary: dict).isEqual(to: $0)
    }
}

if result.isEmpty {
    print("Same key values")
} else {
    print("Diff key values")
}

【讨论】：