Question

如何使用Cocoa计算两个日期之间的月数？

谢谢，斯坦

Answer 1

NSInteger month = [[[NSCalendar currentCalendar] components: NSCalendarUnitMonth
                                                   fromDate: yourFirstDate
                                                     toDate: yourSecondDate
                                                    options: 0] month];

Answer 2

查看NSCalendars components:fromDate:toDate:options方法。它允许您减去日期，然后提取月份属性值

Answer 3

要获得包含一个月份的答案，可以使用以下内容：

- (NSNumber *)numberOfMonthsBetweenFirstDate:(NSDate *)firstDate secondDate:(NSDate *)secondDate {

if ([firstDate compare:secondDate] == NSOrderedDescending) {
    return nil;
}

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *firstDateComponents = [calendar components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit
                                                    fromDate:firstDate];

NSInteger firstDay = [firstDateComponents day];

NSRange rangeOfFirstMonth = [calendar rangeOfUnit:NSDayCalendarUnit inUnit:NSMonthCalendarUnit forDate:firstDate];
NSUInteger numberOfDaysInFirstMonth = rangeOfFirstMonth.length;
CGFloat firstMonthFraction = (CGFloat)(numberOfDaysInFirstMonth - firstDay) / (CGFloat)numberOfDaysInFirstMonth;

// last month component
NSDateComponents *lastDateComponents = [calendar components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit
                                                              fromDate:secondDate];
NSInteger lastDay = [lastDateComponents day];
NSRange rangeOfLastMonth = [calendar rangeOfUnit:NSDayCalendarUnit inUnit:NSMonthCalendarUnit forDate:secondDate];
NSUInteger numberOfDaysInLastMonth = rangeOfLastMonth.length;
CGFloat lastMonthFraction = (CGFloat)(lastDay) / (CGFloat)numberOfDaysInLastMonth;

// Check if the two dates are within the same month
if (firstDateComponents.month == lastDateComponents.month
        && firstDateComponents.year == lastDateComponents.year) {
    NSDateComponents *dayComponents = [calendar components:NSDayCalendarUnit
                                                           fromDate:firstDate
                                                             toDate:secondDate
                                                            options:0];

    NSRange rangeOfMonth = [calendar rangeOfUnit:NSDayCalendarUnit inUnit:NSMonthCalendarUnit forDate:firstDate];
    NSUInteger numberOfDaysInMonth = rangeOfMonth.length;
    return [NSNumber numberWithFloat:(CGFloat)dayComponents.day / (CGFloat)numberOfDaysInMonth];
}

//  Start date of the first complete month
NSDateComponents *firstDateFirstDayOfNextMonth = firstDateComponents;
firstDateFirstDayOfNextMonth.month +=1;
firstDateFirstDayOfNextMonth.day = 1;

// First day of the last month
NSDateComponents *secondDateFirstDayOfMonth = lastDateComponents;
secondDateFirstDayOfMonth.day = 1;

NSInteger numberOfMonths = secondDateFirstDayOfMonth.month - firstDateFirstDayOfNextMonth.month
        + (secondDateFirstDayOfMonth.year - firstDateFirstDayOfNextMonth.year) * 12;

return [NSNumber numberWithFloat:(firstMonthFraction + numberOfMonths + lastMonthFraction)]; 
}

Answer 4

我必须计算两个日期之间的月份变化。这意味着从1月31日到2月1日已过去，MyConnection.retrieve_connection将返回0。

NSCalendar.components

Answer 5

组件：fromDate：toDate：以下示例中的选项无效：

开始日期：2012年1月1日截止日期：2012年3月31日。

使用上述方法的数月= 2

正确的答案应该是3个月。

我使用的计算方法如下： 1.查找开始月份的天数。将其添加到该月的小部分。如果第一个日期是月初，则将其计为完整月份。 2.找到结束月份的天数。将它添加到月份的小部分如果日期是月份的最后一个，则将其计为整月。 3.查找两个日期之间的整个/完整月份，并添加到该月的整数部分。 4.添加整数＆amp;为了获得正确的价值，可以在几个月的时间里分数。

Answer 6

以下是为iOS11更新的@eliocs答案的objective-c版本：

- (NSInteger)monthsSince:(NSDate *)from to:(NSDate *)to {
    NSDateComponents *fromComponents = [[NSCalendar currentCalendar] components:NSCalendarUnitMonth | NSCalendarUnitYear fromDate:from];
    NSDateComponents *toComponents = [[NSCalendar currentCalendar] components:NSCalendarUnitMonth | NSCalendarUnitYear fromDate:to];

    return ((toComponents.year - fromComponents.year) * 12) + (toComponents.month - fromComponents.month);
}

使用Cocoa确定两个日期之间的月数

6 个答案: