Question

NSDate *LastBuildDate;    
NSDate *PubDate;

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyyMMddhhmmss"];
LastBuildDate = [formatter dateFromString:buttoninfoamtion.mLastdate];
PubDate=[formatter dateFromString:newsItem.mPubDate];

   if([PubDate compare:LastBuildDate])

buttoninfomation.mlastdate and newsItem.mPubDate is string from OpenAPI

ex)
buttoninfomation.mlastdate: Tue, 18 Oct 2011 15:54:43 +0900
newspub:Tue, 18 Oct 2011 15:58:00 +0900

but
LastBuidDate = (null)
PubDate = (null)

I want to compare two factor .

So date- date or string- string but I think string – string is so complex.

what wrong up codes?

Answer 1

Well the format you’ve given of “yyyyMMddhhmmss” doesn’t match “Tue, 18 Oct 2011 15:54:43 +0900” even slightly.

Try

EEE, dd MMM yyyy HH:mm:ss Z

as the format string – see the iOS documentation and the Unix TR#35 for more information.