Swift : How to convert String to string with time format?

8
votes

I have string values include time with formatted "HH:mm" (16:50)

i have to convert this value to "hh:mm" format (04:50) as a string in SWIFT

i have tried NSDateFormatter like

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

but its not working.. Please tell any solution.

5
iosswiftnsdateformatter
Just a wild guess.... shouldn't it be var date_from_str = time_format.dateFromString("16:50") ? – Alessandro Da Rugna
why my question get downvote? and first answer erased from page while thats true.. what is going on here – isyap
I don't mean to sound rude, but did you look at the stackoverflow.com/tour ? – Alessandro Da Rugna

5 Answers

15
votes

You need 2 NSDateFormatters, one for dateFromString, one for 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)
7
votes

2020 | SWIFT 5.1:

func dateTimeChangeFormat(str stringWithDate: String, inDateFormat: String, outDateFormat: String) -> String {
    let inFormatter = DateFormatter()
    inFormatter.locale = Locale(identifier: "en_US_POSIX")
    inFormatter.dateFormat = inDateFormat

    let outFormatter = DateFormatter()
    outFormatter.locale = Locale(identifier: "en_US_POSIX")
    outFormatter.dateFormat = outDateFormat

    let inStr = stringWithDate
    let date = inFormatter.date(from: inStr)!
    return outFormatter.string(from: date)
}

usage:

let outStr = dateTimeChangeFormat(str: "16:50", 
                                  inDateFormat:  "HH:mm", 
                                  outDateFormat: "hh:mm")

println(outStr) // -> outputs 04:50
1
votes

I believe you should write the time inside the string. 

    let dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "hh:mm"
    var date = dateFormatter.dateFromString("00:00")
    var str_from_date = dateFormatter.stringFromDate (date)
0
votes

This is an old post, but I think it's worth noting that isLenient allows you to use 1 formatter instead of 2.

func normalizeTimeString(_ original: String) -> String? {
    let formatter = DateFormatter()
    formatter.isLenient = true
    formatter.dateFormat = "hh:mm"

    guard let date = formatter.date(from: original) else { return nil }
    let corrected = formatter.string(from: date)
    return corrected
}

normalizeTimeString("16:50") // Returns "04:50"
0
votes

Can be achieved by using one DateFormatter.

Plus added some extra format in one place. Hope someone get help.

Xcode 12 - Swift 5.3

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm"
var dateFromStr = dateFormatter.date(from: "16:50")!

// Time with date in long format
dateFormatter.dateFormat = "hh:mm:ss a 'on' MMMM dd, yyyy"
var timeInLongFromDate = dateFormatter.string(from: dateFromStr)
print(timeInLongFromDate)
// 04:50:00 PM on January 01, 2000

// Time with customisable format
dateFormatter.dateFormat = "hh:mm:ss a"
var timeFromDate = dateFormatter.string(from: dateFromStr)
print(timeFromDate)
// 04:50:00 PM

// Customisable AP/PM symbols
dateFormatter.amSymbol = "am"
dateFormatter.pmSymbol = "Pm"
dateFormatter.dateFormat = "a"
var amOrPm = dateFormatter.string(from: dateFromStr)
print(amOrPm)
// Pm