Randomly selects a value from from the collection, by weight.

macro.php

<?php

/**
* Returns a random item from the collection based on a weighted value.
* ['foo' => 70, 'bar' => 30] Foo has a 70 percent chance of being returned
* @return int|string
*/
Collection::macro('weightedRandom', function () {
    $sumOfWeights = $this->sum();
    $rand = rand(1, $sumOfWeights);

    foreach ($this as $value => $weight) {
        $rand -= $weight;

        if ($rand <= 0) {
            return $value;
        }
    }
});

Think this would do it too!

Collection::macro('weightedRandom', function () {
    return $this->flatMap(function ($weight, $value) {
        return collect(range(1, $weight))->map(function () use ($value) {
            return $value;
        });
    })->random(); 
});