先看下面的代码

// 如果name和age一个为空则返回nil
func Person(name: String?,age: Int?) ->Bool {
    if name != nil {
        if age != nil {
            return true
        }else {
            return false
        }
    }else {
        return false
    }
}

func Person1(name: String?,age: Int?) ->Bool {
    guard name != nil else {
        return false
        
    }
    guard age != nil else {
        return false
    }
    
    return true
}

func Person2(name: String?,age: Int?) ->Bool {
    guard
        (name != nil),(age != nil)
    else {
        return false
    }
    return true
}

var is0 = Person(name: "gaobo",age: nil)
var is1 = Person1(name: "gaobo",age: nil)
var is2 = Person(name: "gaobo",age: 18)