Question

我正在编写一个函数，它返回一个字典，其中包含最多出现的名称为key，出现次数为value，但是，我收到错误 - 请参阅下面的代码：

let names = ["Adam", "Bob", "Charlie", "Dylan", "Edward"]    

func getMostCommonName(array: [String]) -> [String: Int] {

    var namesDictionary: [String: Int] = [:]  // holds all the names and their occurrences
    var mostCommonNames: [String: Int] = [:]  // will hold the most common name(s) and their occurrences

    for name in array {
        if let count = namesDictionary[name] {
            namesDictionary[name] = count + 1
        }
        else {
            namesDictionary[name] = 1
        }
    }

    let highestOccurence = namesDictionary.values.max()

    for name in namesDictionary {
        if namesDictionary[name] == highestOccurence {
            mostCommonNames[name] = highestOccurence // throws an error
        }
    }

    return mostCommonNames
}

getMostCommonName(array: names)

错误为Cannot subscript a value of type '[String : Int]' with an index of type '(key: String, value: Int)'。我真的不明白为什么会抛出这个错误。任何人？

Answer 1

因为name是(key: String, value: Int)的类型，它是元组类型，你可以像这样访问键和值

for element in namesDictionary {
    if element.value == highestOccurence {
        mostCommonNames[element.key] = highestOccurence
    }
}

另外，我建议像这样写for in

for (key,value) in namesDictionary {
    if value == highestOccurence {
        mostCommonNames[key] = highestOccurence
    }
}

有关元组类型的更多信息：document

Answer 2

你也可以试试这个：

for name in namesDictionary {
    if namesDictionary[name.key] == highestOccurence {
        mostCommonNames[name.key] = highestOccurence 
    }
}

字符串中最常见的名称编译错误

2 个答案: