转换具有未知格式(任何格式)的字符串到目前为止

Question

我有包含日期​​字符串的数据.

通常它会在'Jan. 1966年3月的'类型格式,但由于国际差异,它可能并不总是那样.

我需要读取数据并将其转换为标准日期字符串('YYYY-MM-DD').

基本上这是我到目前为止:

var dataString = 'Jan. 3, 1966'  
var dateFormatter = NSDateFormatter()  
dateFormatter.dateFormat = # I DON'T KNOW THE EXACT INPUT FORMAT !
let dateValue = dateFormatter.dateFromString(dataString)  

Answer 1

Xcode 9•Swift 4或Xcode 8.3.2•Swift 3.1

您可以使用NSDataDetector,如下所示:

extension String {
    var nsString: NSString { return self as NSString }
    var length: Int { return nsString.length }
    var nsRange: NSRange { return NSRange(location: 0, length: length) }
    var detectDates: [Date]? {
        return try? NSDataDetector(types: NSTextCheckingResult.CheckingType.date.rawValue)
                .matches(in: self, range: nsRange)
                .flatMap{$0.date}
    }
}

extension Collection where Iterator.Element == String {
    var dates: [Date] {
        return flatMap{$0.detectDates}.flatMap{$0}
    }
}

测试:

let dateStrings = ["January 3, 1966","Jan 3, 1966", "3 Jan 1966"]
for dateString in dateStrings {
    if let dateDetected = dateString.detectDates?.first {
        print(dateDetected)
        // 1966-01-03 14:00:00 +0000
        // 1966-01-03 14:00:00 +0000
        // 1966-01-03 14:00:00 +0000
    }
}


let dateStrings = ["January 3, 1966","Jan 3, 1966", "3 Jan 1966"]

for date in dateStrings.dates {
    print(date)
    // 1966-01-03 14:00:00 +0000
    // 1966-01-03 14:00:00 +0000
    // 1966-01-03 14:00:00 +0000
}