ios怎么推断日期是周末？

- (NSString *)calculateWeek:(NSDate *)date{
    //计算week数
    NSCalendar * myCalendar = [NSCalendar currentCalendar];
    myCalendar.timeZone = [NSTimeZone systemTimeZone];
    NSInteger week = [[myCalendar components:NSWeekdayCalendarUnit fromDate:date] weekday];
    NSLog(@"week : %zd",week);
    switch (week) {
        case 1:
        {
            return @"周日";
        }
        case 2:
        {
            return @"周一";
        }
        case 3:
        {
            return @"周二";
        }
        case 4:
        {
            return @"周三";
        }
        case 5:
        {
            return @"周四";
        }
        case 6:
        {
            return @"周五";
        }
        case 7:
        {
            return @"周六";
        }
    }
    
    return @"";
}