Question

var dictionary: [String : Any] = [:]
              
for revenueItem in revenues {                        
    if let currentValue = dictionary[revenueItem.customerName] {                    
        dictionary[revenueItem.customerName] = [currentValue] + [revenueItem.revenue]
        print("hellooooooooooo \(currentValue)")
    } else {
        dictionary[revenueItem.customerName] = [revenueItem.revenue]
    }
}

就像我有2个具有相同键但值不同的客户名。我想对它们的值求和，并在输出中只做一个键，但是有一个总值。在我的表格视图中，单元格显示为重复且未汇总值，并且customername（键）也重复。请帮忙..我尝试了一切，但未能纠正输出。

Answer 1

您可以使用Dictionary.init<S>(_ keysAndValues: S, uniquingKeysWith combine: (Value, Value) throws -> Value)，它使用Sequence个元组，存储键值对和一个闭包，闭包定义了如何处理重复的键。

// Create the key-value pairs
let keysAndValues = revenues.map { ($0.customerName, $0.revenue) }
// Create the dictionary, by adding the values for matching keys
let revenueDict = Dictionary(keysAndValues, uniquingKeysWith: { $0 + $1})

测试代码：

struct RevenueItem {
    let customerName: String
    let revenue: Int
}

let revenues = [
    RevenueItem(customerName: "a", revenue: 1),
    RevenueItem(customerName: "a", revenue: 9),
    RevenueItem(customerName: "b", revenue: 1)
]

let keysAndValues = revenues.map { ($0.customerName, $0.revenue) }
let revenueDict = Dictionary(keysAndValues, uniquingKeysWith: { $0 + $1})
revenueDict // ["a": 10, "b": 1]

如何组合字典中的重复键并快速汇总值？

1 个答案: