swift – 按值排序字典键,然后按键排序

我想迭代字典的键,首先按值(降序)排序,然后按键(升序)排序
让dict = [“foo”：1,“bar”：1,“baz”：2,“qux”：2]

迭代的顺序应该是：
[“baz”,“qux”,“bar”,“foo”]

我想打印：

baz 2
qux 2
bar 1
foo 1

Xcode 8 beta 6•Swift 3•Swift 4

extension Dictionary where Value: Comparable {
    var valueKeySorted: [(Key,Value)] {
        return sorted{ if $0.value != $1.value { return $0.value > $1.value } else { return String(describing: $0.key) < String(describing: $1.key) } }
    }
}

let dict = ["foo" : 1,"bar" : 1,"baz" : 2,"qux" : 2]

let keyvalueArray = dict.valueKeySorted

print(keyvalueArray)   // "[("baz",2),("qux",("bar",1),("foo",1)]"

for (key,value) in keyvalueArray {
    print(key,value)
}

Xcode 2.x

let keyvalueArray = dict.sort{ $0.0 < $1.0 }.sort{ $0.1 > $1.1}
print(keyvalueArray)  // [(.0 "baz",.1 2),(.0 "qux",(.0 "bar",.1 1),(.0 "foo",.1 1)]

您还可以创建字典值可比较的扩展名：

extension Dictionary where Value: Comparable {
    var valueKeySorted: [(Key,Value)] {
        return sort{ $0.1 > $1.1 }.sort{ String($0.0) < String($1.0) }
    }
    // or sorting as suggested by Just Another Coder without using map
    var valueKeySorted2: [(Key,Value)] {
        return sort{ if $0.1 != $1.1 { return $0.1 > $1.1 } else { return String($0.0) < String($1.0) } }
    }


}

用法：

let dict = ["foo" : 1,1)]"

如果你想迭代keyvalueArray的元组

for (key,value)
}