Wave-like animation on objects in AS3

I have different cards, I need to reveal them in a wave like form, i.e. the cards open and close at different timings sequentially and systematically such that they form a wave.

I have the cards in an array already. How do I implement this animation in the most efficient way?

presuming what you are meaning is a stadium "wave" effect, try to define an array with an offset, this will depend if you are using a tweening engine etc or if you are using another function.

The Timer class for example will do you well in this one:

private var t:Timer = new Timer(100, 0);
    private var index:int = 0;
    t.addEventListener(TimerEvent.TIMER, ping);
    t.start();

    private function ping(ev:TimerEvent) {
        if(index < waveArray.length){
            waveArray[index].startAnimation(); //If animated by object
            startAnimation(waveArray[index]); //If animated by container
            index ++;
        }
        else {
            t.stop();
            endAnimation(); //All cards have animated
        }
    }