从 random() 生成器创建一个新数组？

Question

I'm trying to create a new array with 5 random names taken from an array with 897 names. This is what I tried to do but I'm not sure how to specify that I only want 5 names:

for(let i = 0; i < pokemon.all().length; i++){
    pokedex = [i];
};
app.get('/dex', (req, res) => {
    res.send(pokedex)
});

Answer 1

Take a look at this, use Math.random() to generate random index and get it from pokemons array, then unset the value from pokemons to have no doublon in pokedex.

 let pokemons = ['pika1','pika2','pika3','pika4','pika5','pika6','pika7'] let pokedex = []; for (i = 0; i < 5; i++) { id = Math.floor(Math.random() * pokemons.length); pokedex.push(pokemons[id]); pokemons.splice(id, 1); } //app.send() here... console.log(pokedex)

EDIT: Considering you have a pokemon.random() generator(?) in this npm package. Simply use:

let pokedex = [];
for(let i = 0; i < 5; i++)    
    pokedex.push(pokemon.random()) };
app.get('/dex', (req, res) => {     
        res.send(pokedex) 
});

Answer 2

 function pickNOf(list, n) { // - create a new shallow array copy. // - does decouple the original reference, thus it // prevents its further mutation by eg `splice`. list = Array.from(list); return Array // - creates an iterable array of the desired length ... .from({ length: n }) // ... thus it can be iterated by eg `map` or `flatMap`. .flatMap(() => // - `splice` does mutate the list by removing a // single item from its randomly chosen index. list.splice(Math.floor(Math.random() * list.length), 1) ); } const listOfAllPokemonNames = [ "Bulbasaur", "Ivysaur", "Venusaur", "Charmander", "Charmeleon", "Charizard", "Squirtle", "Wartortle", "Blastoise", "Caterpie", "Metapod", "Butterfree", "Weedle", "Kakuna", "Beedrill", "Pidgey" ]; console.log( "pickNOf(listOfAllPokemonNames, 5) ...", pickNOf(listOfAllPokemonNames, 5) ); console.log( "pickNOf(listOfAllPokemonNames, 9) ...", pickNOf(listOfAllPokemonNames, 9) ); console.log( "pickNOf(listOfAllPokemonNames, 3) ...", pickNOf(listOfAllPokemonNames, 3) );

 .as-console-wrapper { min-height: 100%!important; top: 0; }

Usage within the OP's code then does look like this ...

function pickNOf(list, n) {
  list = Array.from(list);
  return Array
    .from({ length: n })
    .flatMap(() =>
      list.splice(Math.floor(Math.random() * list.length), 1)
    );
}

app.get('/dex', (req, res) => {
  res.send(pickNOf(pokemon.all(), 5))
});