# Programming-Idioms

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# Idiom #250 Pick a random value from a map

Choose a value x from map m.
m must not be empty. Ignore the keys.

def main(m) do
m
|> Map.values()
|> Enum.random()
end
import 'dart:math';
var x = m.values.toList()[Random().nextInt(m.length)];
import "math/rand"
func pick(m map[K]V) V {
k := rand.Intn(len(m))
i := 0
for _, x := range m {
if i == k {
return x
}
i++
}
panic("unreachable")
}
import "math/rand"
func pick(m map[K]V) V {
k := rand.Intn(len(m))
for _, x := range m {
if k == 0 {
return x
}
k--
}
panic("unreachable")
}
func pick[K comparable, V any](m map[K]V) V {
k := rand.Intn(len(m))
i := 0
for _, x := range m {
if i == k {
return x
}
i++
}
panic("unreachable")
}
import "sync"

var mu sync.RWMutex

func pick(m map[int]any) any {
mu.RLock()
defer mu.RUnlock()
for _, v := range m {
return v
}
return nil
}
// Objects
const values = Object.values(m);

// Maps
const values = [...m.values()];

const x = values[~~(Math.random() * values.length)]
uses fgl;
x := m.Data[Random(m.Count)]);
@vals = values %m;
\$x = \$vals[ int rand @vals ];
import random
x = random.choice(list(m.values()))
x = m.values.sample
use rand::prelude::*;
let mut rng = rand::thread_rng();
let x = m.values().choose(&mut rng).expect("m is empty");

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