How to check NSMutableArray for objects with identical flags?

Question

I have a Card object, that has a flag isFlipped. I store them in a NSMutableArray. I want to check if two objects in my array have the flag on, and if they do, I remove them. As far as I understand I need to iterate over array, but how do I get another object with a flag?

- (void) checkCards
{
    for (Card *card in cards) {

        if (card.flipped)
        {
            if ( ??? )
            {

            }

        }
    }
}

Remember where the first one is while you search for the second? — Hot Licks
– Hot Licks, Commented Nov 13, 2012 at 1:57
Well, first use a regular indexing for loop, so you have a loop index. Then have a "flag 1 index" value that you init to -1. Scan to find the first flag. If "flag 1 index" is -1, change it to your current index and keep scanning. If "flag 1 index" is not -1, you have both flag index values. — Hot Licks
– Hot Licks, Commented Nov 13, 2012 at 2:05

user427969 · Accepted Answer · 2012-11-13 02:12:02Z

1

Store the index of the cards that you want to remove in variables and if the value of both the variables are set then just remove the cards. See the following

- (void) checkCards {
    int card1 = -1;
    int card2 = -1;
    for(int i = 0; i < [cards count]; i++) {
        Card *card = [cards objectAtIndex: i];
        if(card.flipped) {
            if(card1 == -1) {
                card1 = i;
            } else {
                card2 = i;
            }

            if(card1 != -1 && card2 != -1) {
                // remove cards
                break;
            }
        }
    }
}

edited Nov 13, 2012 at 2:12

answered Nov 13, 2012 at 2:05

user427969

3,8966 gold badges54 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

rdelmar · Accepted Answer · 2012-11-13 03:14:39Z

1

I would use the NSArray method, indexesOfObjectsPassingTest:. You can use it like this:

    NSIndexSet *indexSet = [cards indexesOfObjectsPassingTest:^BOOL (Card *obj, NSUInteger idx, BOOL *stop) {
        return obj.isFlipped = YES;
    }];
    [cards removeObjectsAtIndexes:indexSet];

This will remove all cards, whose isFlipped is YES, so if there could be more than 2, and you only want to remove 2, then you would have to iterate through the indexSet and stop after removing 2.

answered Nov 13, 2012 at 3:14

rdelmar

104k13 gold badges210 silver badges222 bronze badges

Collectives™ on Stack Overflow

How to check NSMutableArray for objects with identical flags?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related