function markAnswer(i){
  poll.selectedAnswer = +i;
  try {
    document.querySelector(".poll .answers .answer.selected").classList.remove("selected");
  } catch(msg){}
  document.querySelectorAll(".poll .answers .answer")[+i].classList.add("selected");
  showResults();
}
I understand what [i] mean in array. However, I don't understand what does [+i] mean. I can assume that [+i] is related to array, but I don't know why there is + sign in front of i.
And this code is from YouTube channel called CodingFlag. I watched CodingFlag and found out this code and I try to read and learn something from it, but I can't understand that [+i] part.
 
    