iPhone-如何检查日期是否为星期一？ [英] iPhone - how may I check if a date is Monday?

问题描述

我正在尝试查找日期是否为星期一。

I'm trying to find if a date is Monday.

为此，我将按照以下方式进行操作：

To do this I proceed this way :

#define kDateAndHourUnitsComponents NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit
NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];

// for test and debug purpose
NSDateComponents* b = [calendar components:kDateAndHourUnitsComponents fromDate:retDate];
int a=[[calendar components:kDateAndHourUnitsComponents fromDate:theDate] weekday];
// -----------

if ([[calendar components:kDateAndHourUnitsComponents fromDate:theDate] weekday] == EKMonday) DoThis....

但这不起作用... a和b不包含任何有用的内容（a等于2147483647），

But this doesn't work... a and b does not contain anything useful (a equals 2147483647),

我还想知道 [calendar components：NSWeekdayCalendarUnit fromDate：retDate] 的用途是什么？在那种情况下……

I also wonder what can be the use of [calendar components:NSWeekdayCalendarUnit fromDate:retDate] that is not useful anymore in that case...

我还发现这可以确认这一过程：
如何检查星期几（即星期二） ，星期五？）并比较两个NSDate？

I also found this that confirms the process : How to check what day of the week it is (i.e. Tues, Fri?) and compare two NSDates?

我错过了什么？

推荐答案

在这里，该方法可以通过整数返回日期：7 =星期六，1 =太阳，2 =星期一...

Here ya go, this works and returns days via ints: 7 = Sat, 1 = Sun, 2 = Mon...

目标C

NSDate* curDate = [NSDate date];
int dayInt = [[[NSCalendar currentCalendar] components: NSWeekdayCalendarUnit fromDate: curDate] weekday];

SWIFT 4.2

确定您要检查星期几的日期

let dateComponents = DateComponents(
    year: 2019,
    month: 2 /*FEB*/,
    day: 23 /*23rd day of that month */
)

获取当前日历。

let cal = Calendar.current

现在使用日历检查构建日期是否为有效日期

guard let date = cal.date(from: dateComponents ) else {
    // The date you build up wasn't a valid day on the calendar
    return
}

//Now that your date is validated, get the day of the week

let weekdayIndex = cal.component(.weekday, from: date)

您会注意到'weekdayIndex'是一个整数。如果要使其为字符串，则可以执行以下操作：

if let weekdayName = DateFormatter().weekdaySymbols?[ weekdayIndex - 1] {
    print("The weekday for your date is :: \(weekdayName)")
}

当然，您可以使用 let date = Date（）而是获取星期几是什么

Instead of building your own date, you are of course allowed to use let date = Date() instead to get what the current day of the week is

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