在Swift中从日期字符串转换日期 [英] Converting date from date string in Swift

问题描述

我有一个字符串格式的日期为 2020年1月2日，我想将其转换为 2020年1月2日.

I have a date in string format as 2 January 2020 and I want to convert it as 2nd Jan, 2020.

我尝试使用以下代码，但没有用:

I have tried with following code but of no use:

static func formatDateFromDateTimeString(dateString: String, inputFormat: String = "yyyy-MM-dd'T'HH:mm:ss", outPutFormat:String = "dd MMM yyyy | hh:mm a" )->String {
    let inputDateFormatter = DateFormatter()
    inputDateFormatter.dateFormat = inputFormat
    let date = inputDateFormatter.date(from: dateString)
    let outputDateFormatter = DateFormatter()
    outputDateFormatter.dateFormat = outPutFormat
    if let safeDate = date {
        return outputDateFormatter.string(from: safeDate)
    }
    return ""
}

formatDateFromDateTimeString(dateString: "2 January 2020")

推荐答案

DateFormatter 不支持普通日期格式 1、2nd 例如，您必须自己做

DateFormatter doesn't support the ordinal date format 1st, 2nd you have to do it yourself for example

static func formatDateFromDateTimeString(dateString: String, inputFormat: String = "yyyy-MM-dd'T'HH:mm:ss") -> String? {
    let dateFormatter = DateFormatter()
    dateFormatter.locale = Locale(identifier: "en_US_POSIX")
    dateFormatter.dateFormat = inputFormat
    guard let date = dateFormatter.date(from: dateString) else { return nil }
    let day = Calendar.current.component(.day, from: date)
    dateFormatter.dateFormat = "MMM, yyyy"
    let numberFormatter = NumberFormatter()
    numberFormatter.numberStyle = .ordinal
    guard let dayString = numberFormatter.string(from: day as NSNumber) else { return nil }
    return dayString + " " + dateFormatter.string(from: date)
}

formatDateFromDateTimeString(dateString: "2 January 2020", inputFormat: "dd MMMM yyyy") 

如果要使用此特定日期格式，则 outPutFormat 参数没有任何意义.

The outPutFormat parameter makes no sense if you want this particular date format.

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