Swift： "Cannot invoke subscript" ： 通过在索引处递给一个类的数组来设置对象成员

Question

我在 Swift 编程时遇到了问题。创建 SchedulePatientsTest 类的实例后，我开始收到此错误：无法使用类型为"（名称：$T 4、电子邮件：$T 9、ssn：$T 14、dob：$T 19）"的参数列表调用"下标"

由于我对 Swift 很陌生，所以我在调试它时遇到了麻烦，谷歌搜索也没有多大帮助。我知道它在抱怨数组的下标，但我不明白为什么。感谢您的帮助！

import UIKit
struct SchedulePatientsTest {
let patientNames = [ "John Lennon", "Paul McCartney", "George Harrison", "Ringo Starr" ]
let patientEmails = [ "[e-mail]", "[e-mail]","[e-mail]","[e-mail]"]
let patientSSN = [ "123-45-6789","333-22-1123","567-39-9282","888-88-8888"]
let patientBirthDates = [ "05/01/1951", "06/23/1964","09/05/1955", "02/28/2001"]
let doctorNames = [ "John Smith", "Jane Doe", "Mary Jones", "Beth Garcia"]
let doctorEmails = [ "John Smith", "Jane Doe", "Mary Jones", "Beth Garcia" ]
let doctorSSN = [ "445-25-3382", "582-10-9983", "180-38-0038", "343 - 34-9875" ]
let doctorBirthDates = [ "06/03/1941", "10/10/1950", "12/25/1965", "07/19/1964" ]
let specialty = [ medicalSpecialties.GENERAL_MEDICINE, medicalSpecialties.PEDIATRICS, medicalSpecialties.GENERAL_MEDICINE, medicalSpecialties.ONCOLOGY]
    init()
    {
    }
}
class Patient {
var name  : String = ""
var email : String = ""
var ssn   : String = ""
var dob   : NSDate = NSDate()
init(name: String, email : String, ssn : String, dob : NSDate) {
    self.name = name
    self.email = email
    self.ssn = ssn
    self.dob = dob
}
    func getName()->(String)
    {
        return(name)
    }
}
class Doctor : Patient {
var specialty : medicalSpecialties
    init(specialty: medicalSpecialties,name: String, email : String, ssn : String, dob : NSDate) {
    self.specialty = specialty
    super.init(name: name, email: email, ssn: ssn, dob: dob)
    }
 }
enum medicalSpecialties {
    case GENERAL_MEDICINE
    case PEDIATRICS
    case ONCOLOGY
}
let CMYK = SchedulePatientsTest()
let P1 = Patient(name: CMYK.patientNames[0], email: CMYK.patientEmails[0], ssn: CMYK.patientSSN[0], dob: CMYK.patientBirthDates[0])

Answer 1

这是一个有点模糊的错误消息，但发生错误是因为您正在将字符串而不是 NSDate 传递给患者初始值设定项。

let patientBirthDates = [ "05/01/1951", ...]创建一个字符串对象数组，而不是日期对象。患者初始值设定项需要对其dob参数进行NSDate。

字符串与 NSDate

代码["05/01/1951", "06/23/1964"]不会创建 NSDate 对象数组，即使变量定义为 patientBirtDates: [NSDate] 也是如此。这是什么，是一个字符串文字数组。这些字符串文本被"转换"为String对象。如果要创建 NSDate 对象数组，则需要实际实例化 NSDate 对象：

let patientBirthDates = [ NSDate(timeIntervalSince1970: 100), NSDate(timeIntervalSince1970: 200), NSDate(timeIntervalSince1970: 300) ]

使用哪种创建 NSDates 的方法由您决定，请检查可用的初始化程序。