NSPredicate: unrecognized selector sent to instance when filtering array of NSDateComponents using filteredArrayUsingPredicate

Question

I have some code in which I'm getting an array of dates from now to one year

        NSCalendar* calendar = [NSCalendar currentCalendar];
        NSMutableArray *dateComponentsInRange = [NSMutableArray new];
        NSDate *curDate = [dates objectAtIndex:0];

        while ([curDate timeIntervalSince1970] <= [[dates lastObject] timeIntervalSince1970])
        {
            NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:curDate];
            [dateComponentsInRange addObject:components];
            curDate = [curDate dateWithNextDay];
        }

I need to filter that array(dateComponentsInRange) with another array of date components comparing by day, month, and year.

So far I tried this

        NSDateComponents *components = nil;
        NSMutableArray *predicates = [NSMutableArray array];;
        for (NSDate *currentdate in dates)
        {
            components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:currentdate];
            NSString *preficateFormat = [NSString stringWithFormat:@"(SELF.day  != %d AND SELF.month != %d AND SELF.year != %d)",[components day],[components month], [components year]];
            [predicates addObject:preficateFormat];
        }
        NSPredicate *predicate = [NSCompoundPredicate orPredicateWithSubpredicates:predicates];
        NSArray *filteredArr = [dateComponentsInRange filteredArrayUsingPredicate:predicate];

But I'm getting the following error

 [__NSCFString evaluateWithObject:substitutionVariables:]: unrecognized selector sent to instance

You missed the important part of the error message. What does the rest of it say? — Fogmeister, Sep 05 '14 at 20:22
There are no nil dates in the array I even tried with just one non nil element in the array and still getting that error — Black Sheep, Sep 05 '14 at 20:24

score 3 · Accepted Answer · answered Sep 05 '14 at 21:46

You are adding a string to an array and using it as a predicate.

Try:

    NSDateComponents *components = nil;
    NSMutableArray *predicates = [NSMutableArray array];;
    for (NSDate *currentdate in dates)
    {
        components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:currentdate];
        NSString *preficateFormat = [NSString stringWithFormat:@"(SELF.day  != %d AND SELF.month != %d AND SELF.year != %d)",[components day],[components month], [components year]];
        NSPredicate * predicate = [NSPredicate predicateWithFormat:preficateFormat];
        [predicates addObject:predicate];
    }
    NSPredicate *predicate = [NSCompoundPredicate orPredicateWithSubpredicates:predicates];
    NSArray *filteredArr = [dateComponentsInRange filteredArrayUsingPredicate:predicate];

score 1 · Answer 2 · answered Sep 06 '14 at 05:21

According to Apple Docs orPredicateWithSubpredicates expects an array of NSPredicate but you're passing an array of NSString objects.

The error says

[__NSCFString evaluateWithObject:substitutionVariables:]: unrecognized selector sent to instance

which is correct since evaluateWithObject:substitutionVariables is not defined for NSString but for NSPredicate

Src: Apple Documentation

NSPredicate: unrecognized selector sent to instance when filtering array of NSDateComponents using filteredArrayUsingPredicate

2 Answers2