我有 3 个动物数组:
let mammals = ["Dog", "Cat", "Bear"]
let fish = ["Clownfish", "Seahorse", "Scorpion Fish"]
let reptiles = ["Chameleon", "Snake", "Lizard"]
一个按钮随机生成一个动物,然后将它附加到一个 allAnimals 数组中。我希望能够确定字符串(动物)来自哪个数组。
我试过用
allAnimals.contains()
然而,它显式地接受一个 var 作为参数。我可以做 allAnimals.contains("Seahorse") 就好了。但我需要能够检查所有数组。
我还尝试遍历数组。
for i in allAnimals {
if i.contains(mammals){ print("Came from the Mammal array") }
else if i.contains(fish){ print("Came from the Fish array") }
else if i.contains(reptiles){ print("Came from the Reptiles array") }
}
抛出错误:
Cannot convert value of type '[String]' to expected argument type 'String'
如何确定随机字符串来自哪个数组?
最佳答案
您可以用不同的动物类型定义一个枚举,并构造该枚举动物类型的数组,其中枚举中每个案例的关联值 (String
) 给出了动物的详细信息。
例如
enum Animal: CustomStringConvertible {
case mammal(String)
case fish(String)
case reptile(String)
var description: String {
switch self {
case .mammal: return "Mammal"
case .fish: return "Fish"
case .reptile: return "Reptile"
}
}
var species: String {
switch self {
case .mammal(let s), .fish(let s), .reptile(let s): return s
}
}
}
示例用法:
let mammals = ["Dog", "Cat", "Bear"].map(Animal.mammal)
let fish = ["Clownfish", "Seahorse", "Scorpion Fish"].map(Animal.fish)
let reptiles = ["Chameleon", "Snake", "Lizard"].map(Animal.reptile)
let allAnimals = [reptiles[2], mammals[1]]
for animal in allAnimals {
print("\(animal.species) is a \(animal)")
} /* Lizard is a Reptile
Cat is a Mammal */
关于arrays - 确定字符串来自哪个数组,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41248312/