How to select array element based on rating?

Question

PHP

Ladies and gentlemen, help solve one problem.
Suppose I have an array with data. The numbers are their weight, in percent.:

Ivan => 60
Maxim => 20
Vova => 20

And the task arose to select a random element depending on its weight. For example, the chance that the element "john" will be selected is greater than the others. Because it has more weight.
Tell me how to be?..

Answer 1

The second option is what you need. It remains to get a random from 0 to 4 (with a uniform distribution) and take resp. name. Ivan has just 3/5 chances.
Upd.

function getRandomWinner($ppl)
{
  $choice = rand(0, array_sum(array_values($ppl)) - 1);

  $sum = 0;
  foreach($ppl as $name => $rank) {
    $sum += $rank;
    if ($choice < $sum) return $name;
  }
}

$winnerName = getRandomWinner([
  'Иван' => 60,
  'Максим' => 20,
  'Вова' => 20,
]);