How can we get all the days in selected month

Question

I'm trying to access all the dates from starting to end of the month with the date and day.

struct DateStore {
    static let shared = DateStore()
    
    func monthDays( for selectedDate: Date) -> [Date] {
        var dates = [Date]()
        // if selectedDate 2020/09/01
        // get dates like  [01 Sep, 02 Sep, 03 Sep, 04 Sep ...30 Sep]
        
        // if selectedDate 2020/08/10
        // get dates like  [01 Aug, 02 Aug, 03 Aug, 04 Aug, ...31 Aug]

        return dates
    }
}

If you intend `DateStore` to be a singleton you need to add `private init() {}` - this way there will only be one instance of `DateStore`. — pawello2222, Sep 19 '20 at 21:22

Leo Dabus · Accepted Answer · 2020-09-19T23:29:42.960

5

You can get the range of day in the month, and map the range initializing a new date using the year and month components of the date combined with the day from the range. I am using noon time because not every date starts at 12am:

extension Date {
    func datesInSameMonth(using calendar: Calendar = .current) -> [Date] {
        let year = calendar.component(.year, from: self)
        let month = calendar.component(.month, from: self)
        return calendar.range(of: .day, in: .month, for: self)?.compactMap {
            DateComponents(calendar: calendar, year: year, month: month, day: $0, hour: 12).date
        } ?? []
    }
}

print(Date().datesInSameMonth())  // [2020-09-01 15:00:00 +0000, 2020-09-02 15:00:00 +0000, 2020-09-03 15:00:00 +0000, 2020-09-04 15:00:00 +0000, 2020-09-05 15:00:00 +0000, 2020-09-06 15:00:00 +0000, 2020-09-07 15:00:00 +0000, 2020-09-08 15:00:00 +0000, 2020-09-09 15:00:00 +0000, 2020-09-10 15:00:00 +0000, 2020-09-11 15:00:00 +0000, 2020-09-12 15:00:00 +0000, 2020-09-13 15:00:00 +0000, 2020-09-14 15:00:00 +0000, 2020-09-15 15:00:00 +0000, 2020-09-16 15:00:00 +0000, 2020-09-17 15:00:00 +0000, 2020-09-18 15:00:00 +0000, 2020-09-19 15:00:00 +0000, 2020-09-20 15:00:00 +0000, 2020-09-21 15:00:00 +0000, 2020-09-22 15:00:00 +0000, 2020-09-23 15:00:00 +0000, 2020-09-24 15:00:00 +0000, 2020-09-25 15:00:00 +0000, 2020-09-26 15:00:00 +0000, 2020-09-27 15:00:00 +0000, 2020-09-28 15:00:00 +0000, 2020-09-29 15:00:00 +0000, 2020-09-30 15:00:00 +0000]

edited Sep 19 '20 at 23:29

answered Sep 19 '20 at 21:18

Leo Dabus

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Nicely done. I had forgotten about `range(of:in:for:)`. Plus I like the way you added year and month properties to Date. – Duncan C Sep 19 '20 at 23:10
Of course this extension assumes the current calendar. You might want to add function equivalents for those properties with a `usingCalendar:` parameter that has a default value of `Calendar.current`, so you could call them with other calendars. – Duncan C Sep 19 '20 at 23:10
@DuncanC I have done that also in some other posts. We can simply add the calendar parameter and set the default as the current. – Leo Dabus Sep 19 '20 at 23:20
@DuncanC https://stackoverflow.com/a/62721361/2303865 – Leo Dabus Sep 19 '20 at 23:36
Cool. Did you figure out why the version in your screenshot was returning bad year values? – Duncan C Sep 19 '20 at 23:36
@DuncanC I messed up when editing. swapped year and month – Leo Dabus Sep 19 '20 at 23:41
@LeoDabus *I am using noon time because not every date starts at 12am* - what do you mean? – pawello2222 Sep 20 '20 at 09:47
2

This is to avoid having different times if the date is a daylight savings transition date which might return 1am instead of 12am. For time insensitive calendrical calculations you should always use noon time. – Leo Dabus Sep 20 '20 at 12:24

How can we get all the days in selected month

1 Answers1