从 random() 生成器创建一个新数组？

Question

我正在尝试创建一个新数组，其中包含 5 个随机名称，这些名称取自具有 897 个名称的数组。这是我试图做的，但我不确定如何指定我只想要 5 个名字：

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

Answer 1

function pickNOf(list, n) {
  // - create a new shallow array copy.
  // - does decouple the original reference, thus it
  //   prevents its further mutation by e.g. `splice`.
  list = Array.from(list);

  // - creates and returns an array of the desired length.
  return Array.from({ length: n }, () => list.splice(
    // - `splice` does mutate the list by removing a
    //   single item from its randomly chosen index.
    Math.floor(Math.random() * list.length), 1
  )[0]);
}
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; }

在 OP 代码中的使用看起来像这样......

function pickNOf(list, n) {
  list = Array.from(list);

  return Array.from({ length: n }, () => list.splice(
    Math.floor(Math.random() * list.length), 1
  )[0]);
}

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

Answer 2

看看这个，使用 Math.random() 生成随机索引并从 pokemons 数组中获取它，然后将 pokemons 中的值取消设置为 pokedex 中没有 doublon。

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.slice(i,1)
}
//app.send() here...
console.log(pokedex)

编辑：考虑到你在这个 npm 包中有一个 pokemon.random() generator(?)。只需使用：

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

编辑 N°2：使用对象

let pokedex = [];
for (i = 0; i < 5; i++) {
  let pokemon = {
  name:pokemon.random(),
  attack:Math.floor(Math.random() * (100 - 50 + 1) +50),
  defense:Math.floor(Math.random() * (100 - 50 + 1) +50)
  };
  pokedex.push(pokemon);
}

function attack(attacker,defenser)
{
  defenser.defense -= attacker.attack
  return attacker && defenser;
}

function fakeMatch(attacker,defenser)
{
  attack(attacker,defenser)
}
console.log(pokedex)
fakeMatch(pokedex[0],pokedex[3])
console.log('RESULT Pokedex 0 attacked Pokedex 3')
console.log(pokedex)

编辑 N°3：具有功能的对象（正确方式）

let pokemons = ['pika1', 'pika2', 'pika3', 'pika4', 'pika5', 'pika6', 'pika7']
let pokedex = [];
for (i = 0; i < 5; i++) {
  let id = Math.floor(Math.random() * pokemons.length);
  let pkm = {
    name: pokemons[id],
    life: 100,
    strenght: Math.floor(Math.random() * (100 - 50 + 1) + 50),
    defense: Math.floor(Math.random() * (100 - 50 + 1) + 50),
    attack: function(target) {
      target.life -= this.strenght;
      console.log(this.name + ' attack ' + target.name)
      console.log(target.name + ' loose ' + this.strenght + ' of life')
      //Test if life > 0 or anything else with % defense etc...
      if (target.life <= 0) {
        console.log(target.name + ' is dead')
      }
    }
  };
  pokedex.push(pkm);
  pokemons.slice(id, 1)
}
pokedex[0].attack(pokedex[1]);