从字符串 swift 计算年龄

Question

我正在尝试计算从婴儿到成人（例如 8 周大、4 个月大或 22 岁）的任何人的年龄。但是我的计算失败了，我找不到在哪里。如果我在 2020 年 10 月 16 日输入 DOB，它会返回 8 周大，这是正确的。但是，如果我输入 2020 年 10 月 26 日，它会返回 11 周，这是不正确的。非常感谢任何帮助。

年龄函数：

let bornOn = "10/16/2020"
func calculateAge(dob: String, format: String = "MM/dd/yyyy") -> String{
    let df = DateFormatter()
    df.dateFormat = format
    let date = df.date(from: dob)
    guard let val = date else{
        return ""
    }
    var years = 0
    var months = 0
    var days = 0
    
    let cal = Calendar.current
    years = cal.component(.year, from: Date()) - cal.component(.year, from: val)
    
    let currentMonth = cal.component(.month, from: Date())
    let birthMonth = cal.component(.month, from: val)
    
    months = currentMonth - birthMonth
    
    if months < 0 {
        years = years - 1
        months = 12 - birthMonth
        if cal.component(.day, from: Date()) < cal.component(.day, from: val){
            months = months - 1
        }
    }else if months == 0 && cal.component(.day, from: Date()) < cal.component(.day, from: val){
        years = years - 1
        months = 11
    }
    if cal.component(.day, from: Date()) > cal.component(.day, from: val){
        days = cal.component(.day, from: Date()) - cal.component(.day, from: val)
    }else if cal.component(.day, from: Date()) < cal.component(.day, from: val){
        let today = cal.component(.day, from: Date())
        let date = cal.date(byAdding: .month, value: -1, to: Date())
        days = date!.daysInMonth - cal.component(.day, from: val) + today
    }else{
        days = 0
        if months == 12 {
            years = years + 1
            months = 0
        }
    }
    print("Years: \(years), Months: \(months), Days: \(days)")
    if years > 0{
        if years == 1{
            return "\(years) year old"
        }else{
        return "\(years) years old"
        }
    }else if months > 4{
        return "\(months) months old"
    }else {
        if  months >= 1{
            let daysleftInMonth = months * 30
            print(daysleftInMonth)
            days += daysleftInMonth
        }
       
        let weeks = days / 7
       return "\(weeks) weeks old"
    }
}

extension Date{
     var daysInMonth:Int{
        let calendar = Calendar.current
        
        let dateComponents = DateComponents(year: calendar.component(.year, from: self), month: calendar.component(.month, from: self))
        let date = calendar.date(from: dateComponents)!
        
        let range = calendar.range(of: .day, in: .month, for: date)!
        let numDays = range.count
        
        return numDays
    }
}
calculateAge(dob: bornOn)

Answer 1

你走错了方向。您需要解析日期字符串并将其转换为日期并使用 DateComponentsFormatter 来显示此人的年龄。您还可以获取从生日到今天的日期组件：

extension Formatter {
    static let dateMMddyyyy: DateFormatter = {
        let formatter = DateFormatter()
        formatter.locale = .init(identifier: "en_US_POSIX")
        formatter.dateFormat = "MM/dd/yyyy"
        return formatter
    }()
    static let dateComponents: DateComponentsFormatter = {
        let formatter = DateComponentsFormatter()
        formatter.unitsStyle = .full
        formatter.allowedUnits = [.day, .month, .year]
        formatter.maximumUnitCount = 1
        return formatter
    }()
}

---

extension Date {
    var ageComponents: DateComponents { Calendar.current.dateComponents([.year, .month, .day], from: self, to: Date()) }
    var relativeAge: String {
        Formatter.dateComponents.allowedUnits = ageComponents.month! >= 2 ?
            [.day, .month, .year] : [.weekOfMonth]
        return Formatter.dateComponents.string(from: self, to: Date())! 
    }
}

---

extension String {
    var dateFromMMddyyyy: Date? { Formatter.dateMMddyyyy.date(from: self) }
}

---

"09/10/1970".dateFromMMddyyyy?.relativeAge  // "50 years"
"10/16/2020".dateFromMMddyyyy?.relativeAge  // "2 months"
"10/23/2020".dateFromMMddyyyy?.relativeAge  // "7 weeks"

Answer 2

extension Date {
    func timeAgo() -> String {
        let formatter = DateComponentsFormatter()
        formatter.unitsStyle = .full
        formatter.allowedUnits = [.year, .month, .weekOfMonth ,.day, .hour, .minute, .second]
        formatter.zeroFormattingBehavior = .dropAll
        formatter.maximumUnitCount = 1
        return String(format: formatter.string(from: self, to: Date()) ?? "", locale: .current)
    }
}

在您的方法中使用上述日期扩展

func calculateAge(dob: String, format: String = "MM/dd/yyyy") -> String{
       let df = DateFormatter()
       df.dateFormat = format
       let date = df.date(from: dob)
       return date?.timeAgo() ?? ""
}

像这样使用它，

let date = calculateAge(dob: bornOn)
print(date) //print - 2 weeks