Question

您好亲爱的我想要检索一年中的天数，例如今天是4月10日，我知道它是该月的第10天，但如果我想要像今天这样的一年中的第一天是第99天年。

这是我到目前为止所做的：

NSInteger todaydaysyear;

NSDateFormatter *yearlyDay = [[NSDateFormatter alloc] init];
[yearlyDay setDateFormat:@"dd-yyyy"];
NSDate *currentdateyear = [NSDate date];
NSString *cureentdatestryear = [yearlyDay stringFromDate:currentdateyear];
NSDate *startDateyear = [yearlyDay dateFromString:cureentdatestryear];

NSDateComponents *componentsyear = [[NSCalendar currentCalendar] components:NSCalendarUnitDay | NSCalendarUnitYear fromDate:startDateyear];
todaydaysyear = [componentsyear day];
NSLog(@"here is the day of the year e.g 99th day but not prints month day why%ld", (long)todaydaysyear);

打印：当月10日

我想要的：一年中第99天当天的耳数。

答案：How do you calculate the day of the year for a specific date in Objective-C?

Answer 1

根据Unicode Technical Standard #35，一年中的某一天用D（1..3位数）表示。请记住使用3位数，因为年份可以有365天

[yearlyDay setDateFormat:@"DDD-yyyy"];

输出：

@ “100-2018”

如果要将其存储为整数，请尝试

NSDate *currentDate = [NSDate date];
NSDateFormatter *formatter = [NSDateFormatter new];
[formatter setDateFormat:@"DDD"];
NSString *string = [formatter stringFromDate:currentDate];
NSInteger dayOfYear = [string integerValue];

Answer 2

使用它。

//Assuming your calendar is initiated like this
NSCalendar *_calendar = [NSCalendar currentCalendar];

NSInteger yearlyDay;
//Fetch the weekOfYear number
NSInteger weekOfYear = [_calendar component:NSCalendarUnitWeekOfYear fromDate:[NSDate date]];
weekOfYear--;
//Fetch the weekDay number
NSInteger weekDay = [_calendar component:NSCalendarUnitWeekday fromDate:[NSDate date]];
yearlyDay = weekOfYear*7 + weekDay;
NSLog(@"%d", yearlyDay);

或者这个。

NSCalendar *gregorian =
    [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
    NSUInteger dayOfYear =
    [gregorian ordinalityOfUnit:NSCalendarUnitDay
                         inUnit:NSCalendarUnitYear forDate:[NSDate date]];

    NSLog(@"%d", dayOfYear);

如何以客观c

2 个答案: