获取当前年月日和星期

    NSDate *date1 = [NSDate date];

    NSCalendar *calendar = [NSCalendar currentCalendar];

    NSDateComponents *comps;

// 年月日获得

        comps = [calendar components:(NSCalendarUnitYear |  NSCalendarUnitMonth | NSCalendarUnitDay)

                            fromDate:date];

        NSInteger year = [comps year];

        NSInteger month = [comps month];

        NSInteger day = [comps day];

        NSLog(@"year: %ld month: %ld, day: %ld", (long)year, (long)month, (long)day);

        //    NSCalendarUnitWeekdayOrdinal

        comps = [calendar components:(NSCalendarUnitCalendar | NSCalendarUnitWeekday | NSCalendarUnitWeekdayOrdinal)

                 

                            fromDate:date];

        NSInteger week = [comps weekOfYear]; // 今年的第几周

        NSInteger weekday = [comps weekday]; // 星期几（注意，周日是“1”，周一是“2”。。。。）

        NSInteger weekdayOrdinal = [comps weekdayOrdinal]; // 这个月的第几周

        NSLog(@"week: %ld weekday: %ld ordinal: %ld", (long)week, (long)weekday, (long)weekdayOrdinal);