[英]Given a year and a week number, how do you get the date of the first day of the week?
[英]How to find what day of the week for any given date using Cocoa
我想弄清楚任何特定日期(即2009年6月27日)的哪一天(即周一,周五......)
谢谢。
我一直在做:
NSDateFormatter* theDateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[theDateFormatter setFormatterBehavior:NSDateFormatterBehavior10_4];
[theDateFormatter setDateFormat:@"EEEE"];
NSString *weekDay = [theDateFormatter stringFromDate:[NSDate date]];
这有额外的好处,让您选择如何返回工作日(通过更改setDateFormat中的日期格式字符串:call
有关更多信息,请访问:
您可以查看NSDate和NSCalendar类。 例如, 这里和这里
它们提供以下代码:
NSDate *today = [NSDate date];
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *weekdayComponents =
[gregorian components:(NSDayCalendarUnit | NSWeekdayCalendarUnit) fromDate:today];
NSInteger day = [weekdayComponents day];
NSInteger weekday = [weekdayComponents weekday];
使用NSCalendar和NSDateComponents。 如NSDateComponents文档中所示:
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *date = [gregorian dateFromComponents:comps];
NSDateComponents *weekdayComponents = [gregorian components:NSWeekdayCalendarUnit fromDate:date];
int weekday = [weekdayComponents weekday];
这就是我最终完成的工作,它完全符合预期。 它需要一个日期,将日期更改为该月的第一天 ,并获取该日期的日期:
NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:date];
NSDateComponents *monthDateComponents = [[NSCalendar currentCalendar] components: NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear |
NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond fromDate: date];
// build date as start of month
monthDateComponents.year = components.year;
monthDateComponents.month = components.month;
monthDateComponents.day = 1;
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
// [gregorian setFirstWeekday:1];
NSDate *builtDate =[gregorian dateFromComponents: monthDateComponents];
// NSDateComponents *weekdayComponents =[gregorian components: NSCalendarUnitWeekday fromDate: builtDate];
NSDateFormatter *df = [NSDateFormatter new];
[df setDateFormat:@"E"];
NSString *firstDay = [df stringFromDate:builtDate];
if([firstDay isEqual:@"Sun"]) // do for the other 6 days as appropriate
return 7;
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