How to convert ISO 8601 to date

Question

Created Sep ’20

Replies 5

Boosts 0

Views 4.2k

Participants 3

How do I make a text label in a table view cell show "dd-MM-yyyy " instead of ISO 8601 retrieved from a web service ?

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {



let cell = tableView.dequeueReusableCell(withIdentifier: "cell1", for: indexPath) as! NewsTableViewCell

cell.authorName.text = articles?[indexPath.row].author

cell.headLine.text = articles?[indexPath.row].title

cell.newsImage.downloadImage(from:(self.articles?[indexPath.item].urlImage ?? "nill"))

cell.timePublication.text = articles?[indexPath.row].publishedAt







return cell

}

Boost

Answer 1

Claude31 OP

Sep ’20

You post many questions here, that's good.

But could you please review answers that are proposed and close the thread if the answer solved the problem ? That will help keep the forum clean.

Didn't you get the answer here ?
https://developer.apple.com/forums/thread/660412?answerId=632912022#632912022

Read with a date formatter in the format for 2020-08-22T18:55:36Z

Then build the date from it

and format in the new format
Following works, on the input described in other thread. Note the need to get rid of "T":

Code Block let inputDate = "2020-08-22T18:55:36Z".replacingOccurrences(of: "T", with: " ")
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ssZ"
let date = dateFormatter.date(from: inputDate) ?? Date()
dateFormatter.dateFormat = "yyyy-MM-dd"
print(dateFormatter.string(from: date))

Or you can include 'T' in format:

Code Block let inputDate = "2020-08-22T18:55:36Z" 
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZ"
let date = dateFormatter.date(from: inputDate) ?? Date()
dateFormatter.dateFormat = "yyyy-MM-dd"

More details here:
https://stackoverflow.com/questions/38503489/how-to-convert-date-format-from-dd-mm-yyyy-to-yyyy-mm-dd-in-swift

0

Answer 2

OOPer OP

Sep ’20

Accepted Answer

If you want to work with a certain date format specified in ISO8601, you should better consider using ISO8601DateFormatter.

And creating a DateFormatter is relatively a heavy work in iOS, so you should create an instance outside the method once, and reuse it repeatedly in the method.

The code would be something like this:

Code Block     ///To convert API result date (ISO8601) to `Date`, this property should not be inside any methods
    let inDateFormatter = ISO8601DateFormatter()
    
    ///To convert `Date` to readable date format, this property should not be inside any methods
    let outDateFormatter: DateFormatter = {
        let df = DateFormatter()
        df.dateFormat = "dd-MM-yyyy"
        df.locale = Locale(identifier: "en_US_POSIX")
        return df
    }()
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell1", for: indexPath) as! NewsTableViewCell
        cell.authorName.text = articles?[indexPath.row].author
        cell.headLine.text = articles?[indexPath.row].title
        cell.newsImage.downloadImage(from:(self.articles?[indexPath.item].urlImage ?? "nill"))
        if let dateString = articles?[indexPath.row].publishedAt,
           let date = inDateFormatter.date(from: dateString)
           {
            let formattedString = outDateFormatter.string(from: date)
            cell.timePublication.text = formattedString
        } else {
            cell.timePublication.text = "----------"
        }
 
        return cell
    }

One more, you should better consider adopting Decodable. Some specific date formats like ISO8601 can be converted into Date while decoding JSON.

1

Answer 3

allstar_retro OP

Sep ’20

My apologies, i'll be sure to do that before I post @claude31

0

Answer 4

allstar_retro OP

Sep ’20

@OOPer Thank you so much. Is that a closure or competed property ? The reason for my question is because of the () on line 10

0

Answer 5

OOPer OP

Sep ’20

Is that a closure or competed property ?

It is a closure (line 5 { ... line 10 }), immediately invoked (line 10()). The stored property outDateFormatter is initialized to the returned value of the closure. It's not a computed property.

1