ios - swift : How to convert String to string with time format?

Question

我的字符串值包括时间，格式为 "HH:mm" (16:50)

我必须将此值转换为 "hh:mm"格式 (04:50) 作为 SWIFT 中的字符串

我试过 NSDateFormatter 之类的

let timeFormat = NSDateFormatter()
timeFormat.dateFormat = "hh:mm"
var dateFromStr = timeFormat.dateFromString("16:50")
var strFromDate = timeFormat.stringFromDate(dateFromStr)

但它不起作用.. 请告诉任何解决方案。

Answer 1

你需要 2 个 NSDateFormatter，一个用于 dateFromString，一个用于 stringFromDate

let inFormatter = NSDateFormatter()
inFormatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")
inFormatter.dateFormat = "HH:mm"

let outFormatter = NSDateFormatter()
outFormatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")
outFormatter.dateFormat = "hh:mm"

let inStr = "16:50"
let date = inFormatter.dateFromString(inStr)!
let outStr = outFormatter.stringFromDate(date)
println(outStr) // -> outputs 04:50

Swift 5

let inFormatter = DateFormatter()
inFormatter.locale = NSLocale(localeIdentifier: "en_US_POSIX") as Locale
inFormatter.dateFormat = "hh:mm:ssa"

let outFormatter = DateFormatter()
outFormatter.locale = NSLocale(localeIdentifier: "en_US_POSIX") as Locale
outFormatter.dateFormat = "hh:mm a"
 
let inStr = "16:50"       
let datess = inFormatter.date(from: inStr)!
let outStr = outFormatter.string(from: datess)
print(outstr)