Sorting NSMutableArray using SortDescriptor AND Predicate possible?

Question

I have an array of type \"Restaurant\" which has an NSSet of \"Rating.\" Rating has an ID and a value.

I want to sort the array of Restaurant\'s by rating with an ID

Answer 1

You can sort the array using a NSComparator block.

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"rating_id = %d", ratingID];

NSArray *sorted = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {

    int value1 = [[[[obj1 ratings] filteredSetUsingPredicate:predicate] anyObject] currentValue];
    int value2 = [[[[obj2 ratings] filteredSetUsingPredicate:predicate] anyObject] currentValue];

    if ( value1 < value2 )
        return NSOrderedAscending;
    if ( value1 > value2 )
        return NSOrderedDescending;
    return NSOrderedSame;
}];