create a NSDate from a string - objective-c

Question

I have an NSString like this: #"3/15/2012 9:15 PM" and I would like to convert it to NSDate, I have done like this:
NSString *str =#"3/15/2012 9:15 PM";
NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
[formatter setDateFormat:#"mm/dd/yyyy HH:mm"];
NSDate *date = [formatter dateFromString:];
NSLog(#"%#", date); // date = null
Can you help me please, thanks.

Answer 1

Use the following solution
NSString *str = #"3/15/2012 9:15 PM";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat = #"MM/dd/yyyy HH:mm a";
NSDate *date = [formatter dateFromString:str];
NSLog(#"%#", date);
Edit:
Sorry, the format should be as follows:
formatter.dateFormat = #"MM/dd/yyyy hh:mm a";
And the time shown will be GMT time. So if you add/subtract the timezone, it would be 9:15 PM.
Edit: #2
Use as below. You would get exact time too.
NSString *str = #"3/15/2012 9:15 PM";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat = #"MM/dd/yyyy hh:mm a";
NSTimeZone *gmt = [NSTimeZone timeZoneWithAbbreviation:#"GMT"];
formatter.timeZone = gmt;
NSDate *date = [formatter dateFromString:str];
NSLog(#"%#",date);

Answer 2

Your formatter is wrong. According to the NSDateFormatter documentation it should be "MM/dd/yyyy h:mm a". You also probably want to set the locale as stated in the Date Formatting Guideline:
If you're working with fixed-format dates, you should first set the
locale of the date formatter to something appropriate for your fixed
format. In most cases the best locale to choose is en_US_POSIX, a
locale that's specifically designed to yield US English results
regardless of both user and system preferences.
Try this:
NSString *str = #"3/15/2012 9:15 AM";
NSLocale *enUSPOSIXLocale = [[[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"] autorelease];
NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
[formatter setLocale:enUSPOSIXLocale];
[formatter setDateFormat:#"MM/dd/yyyy h:mm a"];
NSDate *date = [formatter dateFromString:str];
NSLog(#"%#",date);
Outputs:
2012-03-19 12:37:27.531 Untitled[6554:707] 2012-03-15 08:15:00 +0000

Answer 3

Hmmm - you've gone wrong for a couple of reasons
the NSDateFormatter is strict and you have not been.
you didn't supply str to dateFromString:
NSString* str = #"3/15/2012 9:15 PM";
NSDateFormatter* formatter = [[NSDateFormatter alloc]init];
[formatter setDateFormat:#"MM/dd/yyyy HH:mm a"];
NSDate* date = [formatter dateFromString:str];
NSLog(#"%#",date);

Answer 4

NSString *str =#"3/15/2012 9:15 PM";
NSDateFormatter *dateformatter = [[NSDateFormatter alloc]init];
[dateformatter setDateFormat:#"MM/dd/yyyy"];
NSArray *firstSplit = [str componentsSeparatedByString:#" "];
NSDate *dateSelected = [dateformatter dateFromString:[firstSplit objectAtIndex:0]];
[dateformatter setDateFormat:#"mm:ss"];
NSDate *dateSelected2 = [dateformatter dateFromString:[firstSplit objectAtIndex:1]];
NSLog(#"%#",[dateformatter stringFromDate:dateSelected2]);
NSLog(#"%#",[dateformatter stringFromDate:dateSelected]);