如何使用JavaScript检查数组中是否存在子数组

huangapple go评论67阅读模式
英文:

How to check sub array exist in an array using javascript

问题

我正在尝试检查一个子数组是否存在于一个数组中,以便我可以丢弃或避免添加。

例如

假设我有这样一个数组

[
  [-5, 0, 5], [-5, 2, 3], 
  [-3, 0, 3,], [-3, 1, 2], 
  [-1, -1, 2], [-1, 0, 1]
]

并且有另一对作为

[-3, 1, 2]

要添加,但它已经存在于现有数据中,所以需要检查并避免添加。

我迄今为止尝试过的是

let mapped = result.map(item => item.join());
let match = `${item1},${item2},${item3}`; // 即将添加的项目 => item1, item2, item3 
if(mapped.includes(match)){
 ...
} else {
 ...
}

这样使用是否可以,或者有没有更好的方法来在有大量数据时进行检查?

英文:

I'm trying to check whether a sub-array exists in an array so that I could discard or avoid adding.

For example

Let's assume I have an array like this

[
  [-5, 0, 5], [-5, 2, 3], 
  [-3, 0, 3,], [-3, 1, 2], 
  [-1, -1, 2], [-1, 0, 1]
]

and got another pair as
[-3, 1, 2] to add but it's already available in existing data so need to check and avoid adding.

What I have tried so far

let mapped = result.map(item => item.join());
let match = `${item1},${item2},${item3}`; // coming items => item1, item2, item3 
if(mapped.includes(match)){
 ...
} else {
 ...
}

Is this okay to use or any better way to check it when we have a huge amount of data?

答案1

得分: 1

Here is the translated code snippet with the array methods .find() and .every():

const 
    arr = [
        [-5, 0, 5], [-5, 2, 3], 
        [-3, 0, 3,], [-3, 1, 2], 
        [-1, -1, 2], [-1, 0, 1]
    ],
      
    input = [-3, 1, 2],
      
    isIn = (a, b) => b.find(x => x.every((y, i) => y === a[i]))?.length > 0;
      
console.log( isIn(input, arr), arr.length );

isIn(input, arr) || arr.push(input);

console.log( arr.length );

isIn([-3, 1, -2], arr) || arr.push([-3, 1, -2]);

console.log( arr.length );

Please note that I've translated only the code portion as requested, and I've removed the unnecessary comments and HTML escape characters.

英文:

Using array methods .find() and .every():

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

const 
      arr = [
        [-5, 0, 5], [-5, 2, 3], 
        [-3, 0, 3,], [-3, 1, 2], 
        [-1, -1, 2], [-1, 0, 1]
      ],
      
      input = [-3, 1, 2],
      
      isIn = (a,b) =&gt; b.find(x =&gt; x.every((y,i) =&gt; y === a[i]))?.length &gt; 0;
      
console.log( isIn(input, arr), arr.length );

isIn(input, arr) || arr.push(input);

console.log( arr.length );

isIn([-3, 1, -2], arr) || arr.push([-3, 1, -2]);

console.log( arr.length );

<!-- end snippet -->

答案2

得分: 1

我只会返回代码的翻译部分,如下:

我只会迭代您的数组并检查元素是否等于要添加的元素假设您只处理数字您可以通过将数组转换为字符串来检查
const data = [
  [-5, 0, 5],
  [-5, 2, 3],
  [-3, 0, 3],
  [-3, 1, 2],
  [-1, -1, 2],
  [-1, 0, 1]
];
const toAdd = [-3, 1, 2];

const isRowIncludedInMatrix = (matrix, row) =>
  matrix.some(r => r.toString() === row.toString());

if (!isRowIncludedInMatrix(data, toAdd)) // => false -> don't push
  data.push(toAdd);

请注意,这是代码的翻译部分,不包括您的原始问题。

英文:

I would just iterate over your array and check if an element is equal to the element you want to add. Assuming you are only dealing with numbers, you can check that by converting your array to a string.

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

const data = [
  [-5, 0, 5],
  [-5, 2, 3],
  [-3, 0, 3],
  [-3, 1, 2],
  [-1, -1, 2],
  [-1, 0, 1]
];
const toAdd = [-3, 1, 2];

const isRowIncludedInMatrix = (matrix, row) =&gt;
  matrix.some(r =&gt; r.toString() === row.toString());

if (!isRowIncludedInMatrix(data, toAdd)) // =&gt; false -&gt; don&#39;t push
  data.push(toAdd);

<!-- end snippet -->

答案3

得分: 1

如果这是你要处理的唯一数据,简单的比较可能是最好的选择。

some() 和 every() 函数会提前退出:

function addIfNotExists(arrays, newArray) {
  if (!arrays.some(x => x.length === newArray.length && x.every((e, i) => e === newArray[i])))
    arrays.push(x);
}
英文:

If that is the only data you have to work with, a simple comparison might be best.

The some() and every() functions will early exit:.

function addIfNotExists(arrays, newArray) {
  if (!arrays.some(x =&gt; x.length === newArray.length &amp;&amp; x.every((e, i) =&gt; e === newArray[i])))
    arrays.push(x);
}

huangapple
  • 本文由 发表于 2023年6月26日 22:25:47
  • 转载请务必保留本文链接:https://go.coder-hub.com/76557626.html
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定