How to initialise and use array in game assignment

Processing Coding Questions
13

Almost there, guys.
I only have some 1 problem left with void keyPressed() function:

void keyPressed() {
  if (key == 'f') {
    weapon = (weapon + 1) % 10;
  }
  if (key == 'j') {
    if (weapon == invaders[0]){
      remove_invader (weapon);
      add_invader(int(random(10)));
      score = score + 5;
    } else {
      boundary = boundary + 115;
    }
  }
}

The problem is that I don’t know how to obliterate any matching invaders to the right but only the left-most one.