Idiom #11 Pick a random element from a list

List x must be non-empty.

x[Math.floor(Math.random() * x.length)]

const x = [1, 'two', 3, 4, 'five', 'six', 7, 8, 'nine' ];

const randomElement = x[~~(Math.random() * x.length)];

#include <stdlib.h>

x[rand() % x_length];

(rand-nth x)

#include <random>

std::mt19937 gen;
std::uniform_int_distribution<size_t> uid (0, x.size () - 1);
x[uid (gen)];

using System;
using System.Collections.Generic;

x[new Random().Next(x.Count)];

import std.random;

x.randomSample(1);

x[new Random().nextInt(x.length)];

Enum.random(x)

lists:nth(rand:uniform(length(X)), X).

https://github.com/inaka/erlang-katana

ktn_random:pick(X)

call random_number (a)
x(lbound(x) + int(a*ubound(x))

import "math/rand"

func pickT(x []T) T {
	return x[rand.Intn(len(x))]
}

import "math/rand"

x[rand.Intn(len(x))]

import System.Random (randomR)

(\l g -> l !! fst (randomR (0, length l) g))

import System.Random (randomRIO)

(l !!) <$> randomRIO (0, length l - 1)

import java.util.concurrent.ThreadLocalRandom;

x.get(ThreadLocalRandom.current().nextInt(0, x.size()))

x.get((int)(Math.random()*x.size()))

list.random()

(nth (random (length x)) x)

x[math.random(#x)]

x[arc4random_uniform(x.count)]

$x[ array_rand($x) ]

uses classes;

element := x.Items[random(x.count)];

element := x[random(length(x))];

my @x = ('a', 'list', 'of', 'random', 'items');
print $x[rand @x];

import random

random.choice(x)

x.sample

use rand::seq::SliceRandom;

let mut rng = rand::thread_rng();
let choice = x.choose(&mut rng).unwrap();

use rand::{self, Rng};

x[rand::thread_rng().gen_range(0..x.len())]

import scala.util.Random

val x = List(1, 2, 3, 4)
x.apply(Random.nextInt(x.size))

(list-ref x (random (length x)))

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Idiom created by programming-idioms.org

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