Swift如何将字符串转换为NSDate

Question

I've got a date stored in my database and I want to retrieve it and display it nicely in my tableview cells.

The format it comes in from the database and stored in option1 is BO05151530

Where the first two letters have meaning in the program but are not needed for the date so I take those off using the substringFromIndex function.

So what is left is 05151530 where it represents MMddhmm

I would like to display it nicely like MM-dd @ h:mm a

For example 12-05 @ 3:45 am

Here is what I tried but unfortunately ns_date1 comes up as nil each time.

What would you suggest I do?

let date1 = option1.substringFromIndex(option1.startIndex.advancedBy(2))

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "MMddhhmm"

let ns_date1 = dateFormatter.dateFromString(date1)

Answer 1

Try this. you don't need to separate BO NSDateFormatter can handle extra string

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "'BO'MMddHHmm"

let ns_date1 = dateFormatter.dateFromString("BO05151530")

dateFormatter.dateFormat = "'BO' MM-dd @ hh':'mm a"

let string = dateFormatter.stringFromDate(ns_date1!)

Answer 2

try

dateFormatter.dateFormat = "MMddHHmm"

HH is 24 hour format and hh is 12 hour format. you need the 24 one

Answer 3

Check out this app, this will help you know the right format and give you code

https://itunes.apple.com/ae/app/date-format-creator/id965645209?mt=12

NOTE: you need to add year to get a correct NSDate

Answer 4

I have this function :

class func getTheDateString(stringForInputDate: String, fromFormat inputFormat: String, toFormat outputFormat: String) -> String {
let formatter: NSDateFormatter = NSDateFormatter()
formatter.dateFormat = inputFormat
formatter.timeZone = NSTimeZone.localTimeZone()
let dateForInput: NSDate = formatter.dateFromString(stringForInputDate)!
formatter.dateFormat = outputFormat
return formatter.stringFromDate(dateForInput)

}

and used it as:

let stringDate : String = "0515930" // "05151530"

    if stringDate.lengthOfBytesUsingEncoding(NSUTF8StringEncoding) < 8 {

        print([ViewControllerForScreen1 .getTheDateString(stringDate, fromFormat: "MMddHmm", toFormat: "MM-dd @ h:mm a")]);

    }else {

        print([ViewControllerForScreen1 .getTheDateString(stringDate, fromFormat: "MMddHHmm", toFormat: "MM-dd @ h:mm a")]);

    }

OUTPUT:

1. ["05-15 @ 9:30 AM"]

2. ["05-15 @ 3:30 PM"]