CODEWITHSUNDEEP
iphonecocoa-touchnsdatenscalendar
Skoota
Skoota

Reputation: 5290

NSDate for first day of the month

This is quite a simple concept, but as of yet I have been unable to find an elegant (and calendar locale independent) solution. I need to find the first day of the month for an arbitrary NSDate. For example, given an arbitrary NSDate (arbitraryDate) another NSDate object will be returned (let's call this firstDayOfMonthDate) which represents the first day of the month in arbitraryDate. The time component does not matter, as I just need the NSDate object for the first day of the month (although for neatness it would be useful if the time was just zeroed out).

Thanks in advance for any assistance.

Upvotes: 30

Views: 20312

Answers (5)

Ferran Maylinch
Ferran Maylinch

Reputation: 11529

Swift 3:

let calendar = Calendar.current
var comps = calendar.dateComponents([.year, .month], from: date)
comps.setValue(1, for: .day)
let firstDayOfMonth = calendar.date(from: comps)!

// I tried this, but it doesn't work, why?
// let firstDayOfMonth = calendar.date(bySetting: .day, value: 1, of: date)!

Upvotes: 1

Chris Byatt
Chris Byatt

Reputation: 3819

Swift 3

I've included getting the last day of the month in case it is useful to anyone.

extension Date {
    func lastDayOfMonth() -> Date {
        let calendar = Calendar.current
        let dayRange = calendar.range(of: .day, in: .month, for: self)
        let dayCount = dayRange!.count
        var comp = calendar.dateComponents([.year, .month, .day], from: self)

        comp.day = dayCount

        return calendar.date(from: comp)!
    }

    func firstDayOfMonth() -> Date {
        let calendar: Calendar = Calendar.current
        var components: DateComponents = calendar.dateComponents([.year, .month, .day], from: self)
        components.setValue(1, for: .day)
        return calendar.date(from: components)!
    }
}

Upvotes: 4

diciu
diciu

Reputation: 29333

A possible solution:

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *arbitraryDate = [NSDate date];
NSDateComponents *comp = [gregorian components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit) fromDate:arbitraryDate];
[comp setDay:1];
NSDate *firstDayOfMonthDate = [gregorian dateFromComponents:comp];

Upvotes: 72

Digitech
Digitech

Reputation: 292

Swift version

let arbitraryDate:NSDate = NSDate()
let calendar:NSCalendar = NSCalendar.currentCalendar()
let components:NSDateComponents = calendar.components([.Year, .Month, .Day], fromDate: arbitraryDate)
components.setValue(1, forComponent: .Day)
let firstDayOfMonthDate = calendar.dateFromComponents(components)

Upvotes: 1

falsecrypt
falsecrypt

Reputation: 1616

NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear 
                                                               fromDate:[NSDate date]];
components.day = 1;
NSDate *firstDayOfMonthDate = [[NSCalendar currentCalendar] dateFromComponents: components];
NSLog(@"First day of month: %@", [firstDayOfMonthDate descriptionWithLocale:[NSLocale currentLocale]]);

Upvotes: 9

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