Filter fetchRequest for year/month using NSPredicate

Question

I have an app that has several time entries with a date saved as NSDate.

I would like to use a fetch request to filter for a certain year and month that I get from somewhere else. How can I use NSPredicate to filter for a year and month?

let predicate = NSPredicate(format: "%K == %D && %K == %D", ???, selectedMonth, ???, selectedYear)

Update

Using the help Raki pointed out I came up with the following code:

var dateComp = DateComponents()
dateComp.year = Int(selectedYear)
dateComp.month = Int(selectedMonth)
dateComp.day = 1
    
let calendar = Calendar.current
let firstDayOfTheMonth = calendar.date(from: dateComp)
    
var oneMonth = DateComponents()
oneMonth.month = 1
let beginningOfNextMonth = calendar.date(byAdding: oneMonth, to: firstDayOfTheMonth!)

And the predicate:

let predicate = NSPredicate(format: "date >= %@ AND date < %@", firstDayOfTheMonth as! CVarArg, beginningOfNextMonth as! CVarArg)

I get a SIGABRT with the following message:

Could not cast value of type 'Foundation.Date' (0x1073a0ae0) to 'Swift.CVarArg' (0x1196851c8).

Xcode suggested I add "as! CVarArg"

Update 2

The following predicate worked now:

let predicate = NSPredicate(format: "%K >= %@ && %K < %@", "date", firstDayOfTheMonth! as NSDate, "date", beginningOfNextMonth! as NSDate)

it may help : http://stackoverflow.com/questions/13262567/how-to-build-a-nspredicate-filtering-all-days-in-a-month-using-nsdate — Ravi, Feb 22 '17 at 09:09
Thanks raki. But now I get another problem with the fetchRequest at runtime. See above... — , Feb 22 '17 at 09:24
for your new problem http://stackoverflow.com/questions/39587046/cant-pass-date-to-nspredicateformat-without-as-cvararg — Ravi, Feb 22 '17 at 09:30

Nirav D · Accepted Answer · 2017-02-22T09:30:42.130

4

You cannot predicate like this, but you can create two Dates from your month and year which start day of month and end day of month.

Now you need to simply predicate like this way.

let predicate = NSPredicate(format: "%K >= %@ && %K <= %@", "DateAttribute", startDateOfMonth as NSDate, "DateAttribute", endDateOfMonth as NSDate)

Edit: If you don't know how to create date for startDateOfMonth and endDateOfMonth, then you can create it using DateComponents.

let selectedMonth = 11
let selectedYear = 2015
var components = DateComponents()
components.month = selectedMonth
components.year = selectedYear
let startDateOfMonth = Calendar.current.date(from: components)

//Now create endDateOfMonth using startDateOfMonth
components.year = 0
components.month = 1
components.day = -1
let endDateOfMonth = Calendar.current.date(byAdding: components, to: startDate!)

edited Feb 22 '17 at 09:30

answered Feb 22 '17 at 09:07

Nirav D

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Thanks for your help. I just created it myself while you were typing... :P But I like components.day = -1. Didn't know that. – Feb 22 '17 at 09:24
@user7259583 Is it working now, are you getting desired result? – Nirav D Feb 22 '17 at 09:25
@user7259583 Check the edited answer and with predicate type cast `Date` to `NSDate`. like `startDateOfMonth as NSDate` – Nirav D Feb 22 '17 at 09:31
Yes it works now. Used Date instead of NSDate. Thanks for your help. – Feb 22 '17 at 09:32
@user7259583 If you want to know how it is works then read this https://forums.developer.apple.com/thread/60353 – Nirav D Feb 22 '17 at 09:33
@user7259583 Welcome mate :) – Nirav D Feb 22 '17 at 09:33

Filter fetchRequest for year/month using NSPredicate

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