如何从加权列表中选择4个唯一项？

var FRUITS = [
    {name : \"Apple\", weight: 8 },
    {name : \"Orange\", weight: 4 },
    {name : \"Banana\", weight: 4 },
    {name : \"Nectarine\", weight: 3 },
    {name : \"Kiwi\", weight: 1 }
];

var PICKS = 3;

function getNewFruitsAvailable(fruits, removeFruit) {
    var newFruits = [];
    for (var idx in fruits) {
        if (fruits[idx].name != removeFruit) {
            newFruits.push(fruits[idx]);
        }
    }
    return newFruits;
}

var results = [];
var candidateFruits = FRUITS;

for (var i=0; i < PICKS; i++) {
    // CALCULATE TOTAL WEIGHT OF AVAILABLE FRUITS
    var totalweight = 0;
    for (var idx in candidateFruits) {
        totalweight += candidateFruits[idx].weight;
    }
    console.log(\"Total weight: \" + totalweight);

    var rand = Math.random();

    console.log(\"Random: \" + rand);

    // ITERATE THROUGH FRUITS AND PICK THE ONE THAT MATCHES THE RANDOM
    var weightinc = 0;
    for (idx in candidateFruits) {
        // INCREMENT THE WEIGHT BY THE NEXT FRUIT\'S WEIGHT
        var candidate = candidateFruits[idx];
        weightinc += candidate.weight;

        // IF rand IS BETWEEN LAST WEIGHT AND NEXT WEIGHT, PICK THIS FRUIT
        if (rand < weightinc/totalweight) {
            results.push(candidate.name);
            console.log(\"Pick: \" + candidate.name);

            // GET NEXT SET OF FRUITS (REMOVING PICKED FRUIT)
            candidateFruits = getNewFruitsAvailable(candidateFruits, candidate.name);
            break;
        }
    }
    console.log(\"CandidateFruits: \" + candidateFruits.length);
};

for (var i=0; i < results.length; i++) {
    document.write(results[i] + \"<br/>\");
}

[0,1)

function array_rand2($ary,$n = 1)
{
  // make sure we don\'t get in to an infinite loop
  // check we have enough options to select from
  $unique = count(array_unique(array_keys($ary)));
  if ($n > $unique) $n = count($unique);

  // First, explode the array and expand out all the weights
  // this means something with a weight of 5 will appear in
  // in the array 5 times
  $_ary = array();
  foreach ($ary as $item => $weight)
  {
    $_ary = array_merge($_ary, array_fill(0, $weight, $item));
  }

  // now look for $n unique entries
  $matches = array();
  while (count($matches) < $n)
  {
    $r = $_ary[array_rand($_ary)];
    if (!in_array($r,$matches))
    {
      $matches[] = $r;
    }
  }

  // and now grab those $n entries and return them
  $result = array();
  foreach ($matches as $match){
    $result[] = $match;
  }
  return $result;
}

list.elementAt(rand_index++ % size(list))