| 1566 | // If **n** is not specified, returns a single random element. |
| 1567 | // The internal `guard` argument allows it to work with `_.map`. |
| 1568 | function sample(obj, n, guard) { |
| 1569 | if (n == null || guard) { |
| 1570 | if (!isArrayLike(obj)) obj = values(obj); |
| 1571 | return obj[random(obj.length - 1)]; |
| 1572 | } |
| 1573 | var sample = toArray(obj); |
| 1574 | var length = getLength(sample); |
| 1575 | n = Math.max(Math.min(n, length), 0); |
| 1576 | var last = length - 1; |
| 1577 | for (var index = 0; index < n; index++) { |
| 1578 | var rand = random(index, last); |
| 1579 | var temp = sample[index]; |
| 1580 | sample[index] = sample[rand]; |
| 1581 | sample[rand] = temp; |
| 1582 | } |
| 1583 | return sample.slice(0, n); |
| 1584 | } |
| 1585 | |
| 1586 | // Shuffle a collection. |
| 1587 | function shuffle(obj) { |