NSDateFormatter dateFromString Always Returns nil

According to NSDateFormatter documentation :

When working with fixed format dates, such as RFC 3339, you set the dateFormat property to specify a format string.

If your date format is 2017-06-16T17:18:59.082083Z then dateFormat property should look like this yyyy-MM-dd'T'HH:mm:ss.SSSSSSZ.

Swift 3

let dateFormatter = DateFormatter()
let date = "2017-06-16T17:18:59.082083Z"
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSSSSZ"

let result = dateFormatter.date(from: date) // 2017-06-16 17:18:59 +0000

Yet another way to get nil is if you use hh and your hours are on the 24 hr clock and > 12, in that case, you need HH (or H, for zero-padded).

That is:

• Format: yyyy-MM-DD hh:mm:ss, string: "2016-03-01 13:42:17" will return nil
• Format: yyyy-MM-DD HH:mm:ss, string: "2016-03-01 13:42:17" will return the date you expect.

Hat-tip to @neilco (see comments below his answer) for this. If you like this answer, please up-vote his, too.

There are two issues here:

1. The format of date string the formatter is expecting (@"yyyy-MM-dd hh:mm:ss") is different from the format of the date string you're trying to parse (@"EEEE, MMMM d, yyyy 'at' h:mm:ss a zzzz").

2. Setting the formatter's locale to [NSLocale systemLocale] is causing [dateFormat dateFromString:] to return nil. Set it to [NSLocate currentLocale].

The full code for the formatter should be:

    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setTimeZone:[NSTimeZone systemTimeZone]];
    [dateFormat setLocale:[NSLocale currentLocale]];
    [dateFormat setDateFormat:@"EEEE, MMMM d, yyyy 'at' h:mm:ss a zzzz"];
    [dateFormat setFormatterBehavior:NSDateFormatterBehaviorDefault];

    NSDate *date = [dateFormat dateFromString:dateString];