This is a really common question, but mine might be unique since I have long decimal places for the seconds.
NSString *timestamp = #"2015-11-06 15:27:34.0000000";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd'T'HH:mm:ss zzz"];
NSDate *capturedStartDate = [dateFormatter dateFromString: timestamp];
My capturedStartDate is null.
For the date format, I've tried replacing zzz with Z, a, and removing it completely. I've also tried with and without the 'T'. Does someone know the correct format to retrieve this date from the string?
Your date string doesn't have a time zone in it, so you should remove that Z. Also, you have fractions of a second, too. And there's no T in the date string. So you want
yyyy-MM-dd HH:mm:ss.SSSSSS
This does beg the question as to what time zone that string represents. If it is UTC, you'll want to set the time zone of the formatter, accordingly.
Likewise, you might want to be careful about users with non-Gregorian calendars. See Apple Technical Q&A 1480 regarding setting the locale to en_US_POSIX.
Related
In my app , Im using following code to convert string to date before inserting the date into the database.
However this code fails for the users in UK, they have the Region set to UK, and Timezone set to London.
This works for the users in the US as their locale is en_US. So that says, this code works fine for en_US locale but not en_GB locale.
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setLocale:[NSLocale currentLocale]];
[dateFormatter setDateFormat:#"yyyy-MM-dd'T1'HH-mm-ss-SSS"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:#"UTC"]]; //doing this as timestamp stored in server is based on UTC, hence I'm using UTC instead of systemTimeZone
date = [dateFormatter dateFromString:theDate];
The passed string is : 2014-6-26T121-21-6-000
If I set the locale as follows, instead of currentLocale for all the users across the world:
[dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"]];
then the code works, but I would like to know if this cause any issues in future?
Why we need set the locale property for converting the dates ?
Why the currentLocale fails in my case but not the en_US locale even though the date format is matched properly ?
Whenever you’re dealing with ISO 8601 or RFC 3339 dates (i.e. dates exchanged with web services and/or stored as a string in some data store) use en_US_POSIX. See Technical Note 1480.
Or one can use NSISO8601DateFormatter and you don’t have to deal with this locale silliness. E.g.
NSString *string = #"2014-06-26T12:21:06.000Z";
NSISO8601DateFormatter *formatter = [[NSISO8601DateFormatter alloc] init];
formatter.formatOptions = NSISO8601DateFormatWithInternetDateTime | NSISO8601DateFormatWithFractionalSeconds;
NSDate *date = [formatter dateFromString:string];
Also, standard representations of ISO 8601 and RFC 3339 datetime strings, you’d generally use a format like 2014-06-26T12:21:06.000Z where:
the hour is less than 24;
numbers are zero-padded;
separators between hours and minutes and seconds are :;
the separator between seconds and milliseconds is .; and
you'd often add Z at the end of the string to unambiguously designate that the time string is in GMT/UTC/Zulu.
I have integrate RSS feed parser into iOS application. One of the field in the received data is published date. I'm able to parse that date if the iPhone locale is English-United States. But when I change the language of iPhone to Spanish, its not able to convert the string to NSDate object.
Here's the code that I wrote:
NSString* dt = #"Fri, 26 Jun 2015 00:00:00";
NSDateFormatter* dtFormatter = [[NSDateFormatter alloc] init];
//set the locale to spanish
[dtFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:#"es"]];
[dtFormatter setDateFormat:#"EEE, dd MMM yyyy hh:mm:ss"];
NSDate* conDt = [dtFormatter dateFromString:dt ];
NSLog(#"%#", conDt); //This value is always (null)
Even after setting the locale to "es" (which is spanish), its still not able to parse it properly. How can I convert the string to date in iOS?
When you set the locale, you don't want to use the locale of the device, but rather the locale used when the string was created (because you're taking an English string and want to convert it to NSDate regardless of the locale of the device). In fact, it's advised to use en_US_POSIX:
[dtFormatter setLocale:[NSLocale localeWithLocaleIdentifier:#"en_US_POSIX"]];
See Technical Q&A #1480. This focuses on the Gregorian calendar issue with RFC 3999/ISO 8601 date strings, but it is applicable to language settings, too.
By the way, I notice that you're not setting the timezone. Often when dates do not bear any timezone information, they've been converted to GMT/UTC/Zulu. So you may want to set the timezone for your formatter, too:
[dtFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
Given that the time component of your string is "00:00:00", perhaps this isn't significant, but if dealing with datetime strings, you often want to make sure you correctly capture the timezone used within the string, as well.
I have searched over internet for a long time to get this but I can't find the solution. I have received a date string from web services as "22 May 2014", I have to convert into NSDate format for check it with current date. And I have to find out the date from web service is in future or in past time.
The actual problem is that when I convert this using
NSDate *date;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"dd MMMM YYYY"];
date = [dateFormatter dateFromString:dateString];
But I get an entirely Different Date, Sample Input dateString:22 June 2014 and Output I get is 2013-12-21 18:30:00+0000
Please suggest any solutions.
Thanks in advance. :)
You're using YYYY, which doesn't mean what you think it means. From the TR35-31 documentation, Y is the symbol for "year in week-of-year calendars".
You want dd MMMM yyyy instead as your format string. Mixing week-of-year-based fields and regular day/month/year fields is a recipe for odd problems.
Additionally, you may well want to set the time zone in your formatter - if you're just parsing a date, then you should consider using UTC, and make sure that all your calculations and formatting/parsing use UTC.
(I suspect the issue here is that week-of-year hasn't been set, so is assumed to be 1... and the week-year 2014 started on December 30th. Then the day-of-month is set to 22 by the dd part, and then your time zone offset of UTC+05:30 is taken into account.)
I'm having problems using a custom date formatter with NSDateFormatter to convert a string into a date. Here's a short example that creates a string from today's date but fails to convert this back to an NSDate:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"Mdyyyy"];
NSString *example = [dateFormatter stringFromDate:now]; // e.g., 10292013
NSDate *reverse = [dateFormatter dateFromString:example]; // nil?
So basically it seems that NSDateFormatter is creating a date string that it itself can't turn back into a NSDate using the same format that created the string.
Using MMddyyyy as the date string works, although I can't see from the documentation (which conveniently only goes up to iOS 6.0) why it would matter:
month M 1..2 09 Month - Use one or two for the numerical month, ....
...
day d 1..2 1 Date - Day of the month
The reason why I'm trying to use Mdyyyy instead of MMddyyyy is because it's closer to what NSDateFormatterShortStyle returns for my current NSLocale (M/d/yy).
Perhaps someone might have some insight here as two what I'm doing wrong, or if I'm wrong in my understanding of how this should work. (I know there are a lot of questions here regarding NSDateFormatter, but I didn't find one that fits my problem.)
Mdyyyy is ambiguous as a string ->date mapping. One cannot tell if "1112013" is Jan 11 or November 1. Hence NSDateFormatter will not allow it for string ->date.
When I am printing the date
//getting the current date and time
self.date = [NSDate date];
NSLog(#"%#",date);
The date which I am getting is correct, but there is a delay in time by 6 hrs. My system time is correct.
try this
NSLocale* currentLoc = [NSLocale currentLocale];
NSLog(#"%#",[[NSDate date] descriptionWithLocale:currentLoc]);
Make use of NSDateFormatter
NSDate *today = [NSDate date];
//Create the dateformatter object
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
//Set the required date format
[dateFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
//Get the string date
NSString *dateString = [dateFormatter stringFromDate:today];
//Display on the console
NSLog(dateString);
Logging an NSDate in the debugger is somewhat misleading as it gives you a calendar day and time for a particular time zone - UTC / GMT. However, NSDate has no inherent time zone or any inherent relationship to how humans perceive and think about dates at all. Instead, it is a timestamp. Classes like NSDateComponents, NSTimeZone, NSDateFormatter, and so on all exist to provide human context and formatting.
So what you see is the timestamp formatted to that particular format and UTC time zone, which is how NSDate will always appear when printed in the debugger or the console. If you were to calculate the time zone offset between UTC and your own time zone, you'd find that the date represents the time stamp you gave it, and not one however many hours off.
you can set current time zone for customizing your date format.
This link can help:
https://stackoverflow.com/a/7213629/456471
The default date string representation is probably formatting the date as UTC, rather than your local time zone (the exact format that it will use is not defined, and may change from release to release, so you shouldn't rely on it). You should use the NSDateFormatter class if you need to format a date in a particular format (or with a particular time zone, including the local time zone); see the Data Formatting Guide and the NSDateFormatter Class Reference for more information.