我有两个日期 StartDate 和 EndDate。我想在这两个日期之间找到特定的日子,例如星期一。
如何在两个日期之间执行循环?
这个问题实际上有两个部分:
你可以用NSCalendar
得到一个星期一。在下面的代码中,我使用当前日历并将一周的第一天更改为星期一,然后将日期设为“一周的开始”。这是我从这个答案中学到的一个技巧。
NSDate *loopDate = // the start date you are looping from
NSCalendar *currentCalendar = [NSCalendar currentCalendar];
currentCalendar.firstWeekday = 2; // Monday
[currentCalendar rangeOfUnit:NSWeekCalendarUnit startDate:&loopDate interval:NULL forDate:loopDate];
当我现在运行它时(我的循环日期是 3 个月前),它会Friday, May 17, 2013 at 5:57:26 PM GMT+2
变成Monday, May 13, 2013 at 12:00:00 AM GMT+2
(之前的星期一)。
这真的很简单。为“一周”创建日期组件并将其添加到日期,只要它小于结束日期即可。
NSDateComponents *oneWeek = [NSDateComponents new];
oneWeek.week = 1;
while ([loopDate compare:endDate] == NSOrderedAscending) {
loopDate = [currentCalendar dateByAddingComponents:oneWeek toDate:loopDate options:0];
// Do something with the date
}
当我运行此代码并记录我得到的日期时:
Monday, May 20, 2013 at 12:00:00 AM GMT+2
Monday, May 27, 2013 at 12:00:00 AM GMT+2
Monday, June 3, 2013 at 12:00:00 AM GMT+2
Monday, June 10, 2013 at 12:00:00 AM GMT+2
Monday, June 17, 2013 at 12:00:00 AM GMT+2
Monday, June 24, 2013 at 12:00:00 AM GMT+2
Monday, July 1, 2013 at 12:00:00 AM GMT+2
Monday, July 8, 2013 at 12:00:00 AM GMT+2
Monday, July 15, 2013 at 12:00:00 AM GMT+2
Monday, July 22, 2013 at 12:00:00 AM GMT+2
Monday, July 29, 2013 at 12:00:00 AM GMT+2
Monday, August 5, 2013 at 12:00:00 AM GMT+2
Monday, August 12, 2013 at 12:00:00 AM GMT+2
Monday, August 19, 2013 at 12:00:00 AM GMT+2
使用NSCalendar
和NSDateComponents
将时间段添加到日期。然后,您可以循环并重复添加句点,直到compare:
表明您已经过了结束日期。