基于另一个数组按值过滤数组答案

【问题标题】：filter array by value based on another array基于另一个数组按值过滤数组
【发布时间】：2020-12-03 16:51:24
【问题描述】：

我有一堆卡片。我需要根据另一个数组按值字过滤它。只有那些对象应该保留在与数组 hardWords 中的名称相对应的卡片中

const cards = [ 
  {
      word: 'cry',
    },
    {
      word: 'fishing',
    },
    {
      word: 'fly',
    },
    {
      word: 'hug',
    },
  ],
  [
    {
      word: 'open',
    },
    {
      word: 'play',
    },
    {
      word: 'run',
    },
    {
      word: 'sing',
    },
  ],
.....
let difficultWords = ["cry", "run", "sing"];

这是我的代码：（但 id 不起作用）

 let wrongCard = cards.forEach(card => {
    card.filter(el => difficultWords.forEach(i => el.word === i));
 }

输出应该是

let wrongCard = [ 
  [
    {
      word: 'cry',
    },
  ],
  [
    {
      word: 'run',
    },
    {
      word: 'sing',
    },
]

【问题讨论】：

预期输出与输入有何关系？

标签： javascript arrays filter

【解决方案1】：

const cards = [
  [
    {
      word: 'cry'
    },
    {
      word: 'fishing'
    },
    {
      word: 'fly'
    },
    {
      word: 'hug'
    }
  ],
  [
    {
      word: 'open'
    },
    {
      word: 'play'
    },
    {
      word: 'run'
    },
    {
      word: 'sing'
    }
  ]
];
let difficultWords = ['cry', 'run', 'sing'];

const wrongCard = cards.map((card) =>
  card.filter((c) => difficultWords.includes(c.word))
);

console.log(wrongCard);

【讨论】：

它无法正常工作。它返回一个数组中与所需对象一起的其他对象
@rise 你能用准确的输入和期望值更新你的帖子吗？

【解决方案2】：

您可以为此使用.map 和.includes。

let wrongCard = cards.forEach(card => {
    card.filter(el => difficultWords.forEach(i => el.word === i));
 }

因为你写了let wrongCard = cards.forEach...，所以我假设你想将结果分配给wrongCard。

要将一个数组转换为另一个数组，应使用.map，因为.forEach 将返回undefined。

接下来，因为difficultWords是字符串数组，而word也是字符串，要检查一个值是否在数组内，我们可以使用diffultWords.includes(word)，这将返回true是包含的单词在diffultWords中。

const cards = [
  [{ word: "hug" }],
  [{ word: "open" }, { word: "play" }, { word: "hug" }],
  [{ word: "point" }],
];
let difficultWords = ["point", "hug", "frog", "lion"];

const result = cards.map((arr) => {
  return arr.filter((value) => {
    return difficultWords.includes(value.word);
  });
});

console.log(result)

【讨论】：

【解决方案3】：

您可以使用Array#map 使用过滤后的值创建一个新数组。

const cards = [ 
  [{
      word: 'cry',
    },
    {
      word: 'fishing',
    },
    {
      word: 'fly',
    },
    {
      word: 'hug',
    },
  ],
  [
    {
      word: 'open',
    },
    {
      word: 'play',
    },
    {
      word: 'run',
    },
    {
      word: 'sing',
    },
  ]];
let difficultWords = ["cry", "run", "sing"];
const res = cards.map(x => x.filter(({word}) => difficultWords.includes(word)));
console.log(res);

【讨论】：

【解决方案4】：

成功了，恭喜！！！！

const cards = [
  [{ word: "hug" }],
  [{ word: "open" }, { word: "play" }, { word: "hug" }],
  [{ word: "point" }],
];
let difficultWords = ["point", "hug", "frog", "lion"];

let res = [];
difficultWords.forEach(val => {
  cards.map(item => {
  item.map(e =>{
  if(e.word === val) {
   res.push(e)
  }})
  })
})

console.log(res)

【讨论】：