Please help me understand arrays

[foxfire]

i don’t understand how arrays work (the kind that you use to see which enemy has least health, which coin is farthest, etc.). can someone please explain?
i can’t figure out alone how to win all the levels in the desert and use this forum a lot (it’s not a bad thing, i just want to know it myself…)

[jka2706]

Hi foxfire,

Good question! An array is just a list. It can be a list of numbers, or words, or enemies, or lots of other things. It is contained by square brackets [ ], and usually - but not always - the elements are separated by commas.

The first element in an array is labelled 0, the second is labelled 1 etc. So you can call the first element with array[0].

I find that sometimes it helps to see the array, and in CoCo you can generally just put in hero.say(array); or hero.say(array[5]) if you want to see the sixth element.

Does that answer your question, or do you want more information?

Jenny

[foxfire]

@jka2706, my problem is with using arrays in a code.
for example:

while(true) {
    var coins = hero.findItems();
    var coinIndex = 0;
    var nearest = null;
    var nearestDistance = 9999;
    while(coinIndex < coins.length) {
        var coin = coins[coinIndex];
        coinIndex++;
        var distance = hero.distanceTo(coin);
        if (coin.distance < nearestDistance) {
            nearest = coin;
            nearestDistance = coin.distance;
        }
    }
    if (nearest) {
        hero.moveXY(nearest.pos.x, nearest.pos.y);
    }
}

the hero just stands there and doesn’t move…
it happens to me in all array levels, can you see what I’m doing wrong?

[AnSeDra]

@foxfire

coinIndex++;

What happens if you put this at the end of the second while loop?

Andrei

[foxfire]

sorry, it doesn’t work…

[foxfire]

I saw that it was supposed to be

distance

and not

coin.distance

but it still wouldn’t work…
any other ideas?

[xython]

Maybe you didn’t replace all "coin.distance"s with “distance”…
this will work:

    while(coinIndex < coins.length) {
        var coin = coins[coinIndex];
        coinIndex++;
        var  distance = hero.distanceTo(coin);
        if (distance < nearestDistance) {
            nearest = coin;
            nearestDistance = distance;
    }

and this is also OK:

    while(coinIndex < coins.length) {
        var coin = coins[coinIndex];
        coinIndex++;
        coin.dist = hero.distanceTo(coin);
        if (coin.dist < nearestDistance) {
            nearest = coin;
            nearestDistance = coin.dist;
        }
    }

Don’t use coin.distance, you’ll get this error:

[foxfire]

works perfectly. thank you!
I guess my arrays problems where because I didn’t place my coinIndex++ in the right place.
thanks for the explanation of arrays and level help

[xython]

@jka2706
in an array usually - but not always - the elements are separated by commas
I suppose you are right - can you show an array where the elements aren’t separated by commas ( I suck more at python than in java script)

[jka2706]

I’m just going off the instructions for https://codecombat.com/play/level/the-spy-among-us.

They include:

// This function checks for a specific letter in a word.
// A string is just an array! Loop over it like an array

Instructions the same in JS and python. No commas .

Jenny

[xython]

Apparently pets know arrays and coding better than me

[foxfire]

Hahaha! smart cougar