swift - 字符串编译错误中最常出现的名称

Question

我正在编写一个函数，它返回一个字典，其中包含出现次数最多的名称作为 key，出现次数作为 value，但是，我得到了一个错误 - 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)

错误是无法使用类型为“(key: String, value: Int)”的索引下标类型为“[String : Int]”的值。我真的不明白为什么会抛出这个错误。有没有人要？

Answer 1

因为name是(key: String, value: Int)的类型，是元组类型，可以这样访问key和value

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

此外，我建议像这样编写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