Swift 2 - 使用从A到Z的键将数组分离到字典中

Question

我有一个数组,例如["Apple", "Banana", "Blueberry", "Eggplant"],我想将其转换为如下字典:

[
    "A" : ["Apple"],
    "B" : ["Banana", "Blueberry"],
    "C" : [],
    "D" : [],
    "E" : ["Eggplant"]
]

我在Xcode 7 beta 4上使用Swift 2.谢谢!

Answer 1

仅使用Swift 2对象和方法,并使用字母表中每个字母的键:

let alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".characters.map({ String($0) })

let words = ["Apple", "Banana", "Blueberry", "Eggplant"]

var result = [String:[String]]()

for letter in alphabet {
    result[letter] = []
    let matches = words.filter({ $0.hasPrefix(letter) })
    if !matches.isEmpty {
        for word in matches {
            result[letter]?.append(word)
        }
    }
}

print(result)