JavaScript：在2D数组中删除重复

Question

我在JavaScript中有一个像这样的2D数组：

result=[["user1", "java"], ["user2", "python"],["user1", "java"], ["user1", "C++"], ["user1", "java"], ["user2", "Python"]....]  

您可以看到 [“ user1”，“ java”] 来了3次， [“ user2”，“ python”] 2次。

我想清洁此数组，以便每个几个元素只能出现一次。这意味着如果“ user1”可以再次出现，则应使用另一种语言，而不是“ java”。 有人可以帮我吗？

Answer 1

您可以使用 降低 ， join 和

const result = [
    ['user1', 'java'],
    ['user2', 'python'],
    ['user1', 'java'],
    ['user1', 'C++'],
    ['user1', 'java'],
    ['user2', 'python'],
];

const [uniqueElements] = result.reduce((acc, curr) => {
        const [uniq, set] = acc;
        if (!set.has(curr.join(','))) {
            set.add(curr.join(','));
            uniq.push(curr);
        }
        return acc;
    },
    [[], new Set()],
);

console.log(uniqueElements);

/* This is not a part of answer. It is just to give the output full height. So IGNORE IT */
.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

您可以尝试这个：

let result= [
  ["user1", "java"], 
  ["user2", "python"],
  ["user1", "java"], 
  ["user1", "C++"], 
  ["user1", "java"], 
  ["user2", "Python"]
];
const map = new Object();
result.forEach((item) => {
  if(!map[item[0]]){
    map[item[0]] = new Array();
  }
  const user = map[item[0]];
  const language = (item[1] || '').toLowerCase().trim();
  if(user.indexOf(language) < 0){
    user.push(language);
  }
});
result = new Array();
Object.keys(map).forEach((user) => {
  map[user].forEach((language) => {
    result.push([user,language]);
  });  
});
console.log(result);

Answer 3

您可以创建一个通过加入用户和语言字符串，从数组中删除重复项。然后只需将字符串拆分回到所需的数组即可。

const 
  result = [["user1", "java"], ["user2", "python"], ["user1", "java"], ["user1", "c++"], ["user1", "java"], ["user2", "python"]],
  uniques = Array.from(new Set(result.map((res) => res.join("-")))).map(
    (data) => data.split("-")
  );

console.log(uniques);

相关文档：

• href = href =“ https://developer.mozilla.org/en-us/docs/web/javascript/Reference/global_objects/array/mmap” rel =“ nofollow noreferrer”
• > href =“ https://developer.mozilla.org/en-us/docs/web/javascript/Reference/global_objects/array/aray/join” rel =“ nofollow noreferrer”> arne.protototype.join
• href =“ https://developer.mozilla.org/en-us/docs/web/javascript/reference/global_objects/string/split/split” rel =“ nofollow noreferrer”