计算星期

NSDateFormatter *inputFormatter = [[NSDateFormatter alloc] init];[inputFormatter setDateFormat:@"yyyy-MM-dd 'at' HH:mm"];NSDate *formatterDate = [inputFormatter dateFromString:@"2012-01-01 at 07:30"];[inputFormatter release];NSDateFormatter *outputFormatter = [[NSDateFormatter alloc] init];[outputFormatter setDateFormat:@"HH:mm 'on' EEEE MMMM d"];NSString *newDateString = [outputFormatter stringFromDate:formatterDate];[outputFormatter release];NSLog(@"%@", newDateString); //07:30 on Sunday January 1