在快速格式化后日期不正确

Question

我按照我的代码分隔了日期和时间，然后我使用了DateFormatter，但是日期不正确。为什么？

像这样：Optional("08/15/0020")

  var formateFromdate: String?
  var formateTodate: String?

  func addDate(){

  var fromDateArr = fromDateLabel.text!.components(separatedBy: ",")
        fromDate = fromDateArr[0]
        fromTime = fromDateArr[1].replacingOccurrences(of: " ", with: "")
  var toDateArr   = toDateLabel.text!.components(separatedBy: ",")
        toDate = toDateArr[0]
        toTime  = toDateArr[1].replacingOccurrences(of: " ", with: "")
        
        let inputFormatter = DateFormatter()
        inputFormatter.dateFormat = "MM/dd/yyyy"
                 
        let showDateFrom = inputFormatter.date(from: fromDate)
        inputFormatter.dateFormat = "MM/dd/yyyy"
        formateFromdate = inputFormatter.string(from: showDateFrom!)
        print(formateFromdate)
        }

注意:这里的fromDate = 08/15/2020 是正确的，但在格式化日期之后没有正确的

OutPut:

    Optional("08/15/0020") it should be 08/15/2020

Answer 1

从格式化的日期输出来看，fromDate = fromDateArr[0]的值似乎是"08/15/20"，如果是这样的话，您必须使用如下的日期格式；

    let inputFormatter = DateFormatter()
    inputFormatter.dateFormat = "MM/dd/yy"
    
    let showDateFrom = inputFormatter.date(from: fromDate)
    inputFormatter.dateFormat = "MM/dd/yyyy"
    let formateFromdate = inputFormatter.string(from: showDateFrom!)
    print(formateFromdate)

Answer 2

你需要先拆开它

if let formate = inputFormatter.string(from: showDateFrom!){
        print(formate)
}