我想要做的是获取两个日期之间每月特定日期的次数.
例如：
我想要在2011年11月21日至2013年5月15日期间每月16日过多少次.
在这种情况下,它将是17.
我一直在努力解决这个问题.我知道如何解决这个问题的唯一方法是编写一堆if语句来检查已经过了多少年,然后已经过了多少个月等等.有没有更快的方法,比如使用NSDate或其他什么？
解决方法
好的,这是一个
gist的工作示例.代码的内容是：
const NSCalendarUnit units = NSEraCalendarUnit|NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSCalendarCalendarUnit|NSTimeZoneCalendarUnit;
NSDateComponents *comps = [calendar components:units
fromDate:startDate];
if ([comps day] > wantDay)
nextMonth(comps); // Missed the first month
[comps setDay:wantDay];
NSInteger count = 0;
while (YES) {
NSDate *compareDate = [calendar dateFromComponents:comps];
if (!compareDate) {
NSLog(@"Failed to create compare date");
return 5;
}
NSLog(@"Comparing %@",[formatter stringFromDate:compareDate]);
if ([compareDate compare:endDate] == NSOrderedDescending)
break;
count++;
nextMonth(comps);
}
nextMonth()的位置是：
static void nextMonth(NSDateComponents *comps) {
NSInteger month = [comps month];
if (month == 12) {
[comps setYear:[comps year] + 1];
[comps setMonth:1];
} else {
[comps setMonth:month + 1];
}
}
示例输出：
$./dateiter 19990112 19990212 12 2014-01-16 13:06:53.189 dateiter[16740:707] start-date=1999-01-12 00:00:00 +0000,end-date=1999-02-12 00:00:00 +0000,want-day=12 2014-01-16 13:06:53.189 dateiter[16740:707] Comparing 19990112 2014-01-16 13:06:53.190 dateiter[16740:707] Comparing 19990212 2014-01-16 13:06:53.190 dateiter[16740:707] Comparing 19990312 2014-01-16 13:06:53.190 dateiter[16740:707] 2 months $./dateiter 20111121 20130515 16 2014-01-16 13:10:53.318 dateiter[16810:707] start-date=2011-11-21 00:00:00 +0000,end-date=2013-05-15 00:00:00 +0000,want-day=16 2014-01-16 13:10:53.319 dateiter[16810:707] Comparing 20111216 2014-01-16 13:10:53.319 dateiter[16810:707] Comparing 20120116 2014-01-16 13:10:53.319 dateiter[16810:707] Comparing 20120216 2014-01-16 13:10:53.319 dateiter[16810:707] Comparing 20120316 2014-01-16 13:10:53.320 dateiter[16810:707] Comparing 20120416 2014-01-16 13:10:53.320 dateiter[16810:707] Comparing 20120516 2014-01-16 13:10:53.320 dateiter[16810:707] Comparing 20120616 2014-01-16 13:10:53.320 dateiter[16810:707] Comparing 20120716 2014-01-16 13:10:53.321 dateiter[16810:707] Comparing 20120816 2014-01-16 13:10:53.321 dateiter[16810:707] Comparing 20120916 2014-01-16 13:10:53.321 dateiter[16810:707] Comparing 20121016 2014-01-16 13:10:53.322 dateiter[16810:707] Comparing 20121116 2014-01-16 13:10:53.322 dateiter[16810:707] Comparing 20121216 2014-01-16 13:10:53.322 dateiter[16810:707] Comparing 20130116 2014-01-16 13:10:53.322 dateiter[16810:707] Comparing 20130216 2014-01-16 13:10:53.323 dateiter[16810:707] Comparing 20130316 2014-01-16 13:10:53.323 dateiter[16810:707] Comparing 20130416 2014-01-16 13:10:53.323 dateiter[16810:707] Comparing 20130516 2014-01-16 13:10:53.323 dateiter[16810:707] 17 months
