String description of NSDate

Question

I have the following code:

[ [NSDate date] descriptionWithLocale: @\"yyyy-MM-dd\" ]

I want it to return a date in the following format: \"2009-

Answer 1

You are using the wrong method. Instead try descriptionWithCalendarFormat:timeZone:locale:

[[NSDate date] descriptionWithCalendarFormat:@"%Y-%m-%d"
                                    timezone:nil
                                      locale:nil];

Also note that the method is expecting a different format than the one in your question. The full documentation for that can be found here.

EDIT: Though as Mike noted, you really should be using NSDateFormatter. There are some problems with descriptionWithCalendarFormat:timezone:locale: that Apple mentions in the documentation.

Answer 2

NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd"];
NSString *dateString = [dateFormatter stringFromDate:[NSDate date]];
[dateFormatter release];  // delete this line if your project uses ARC
NSLog(@"%@",dateString); 

Answer 3

If you don't have NSDate -descriptionWithCalendarFormat:timeZone:locale: available (I don't believe iPhone/Cocoa Touch includes this) you may need to use strftime and monkey around with some C-style strings. You can get the UNIX timestamp from an NSDate using NSDate -timeIntervalSince1970.

Answer 4

Also note that for most cases, NSDateFormatter is to be preferred for its flexibility.

There's also a significant performance benefit to be had from re-use of date formatters in many apps.