如何从json字符串中递归获取父ID答案

【问题标题】：How to fetch parent ids recursively from json strings如何从json字符串中递归获取父ID
【发布时间】：2020-02-19 07:36:55
【问题描述】：

{
  "id": "1",
  "name": "root",
  "children": [
    {
      "id": "1.1",
      "name": "Child 1",
      "children": [
        {
          "id": "1.1.1",
          "name": "Child 1-1",
          "children": [
            {
              "id": "1-1-1",
              "name": "Child 1-1-1",
              "children": [

              ]
            }
          ]
        },
        {
          "id": "1.1.2",
          "name": "Child 1-2",
          "children": [

          ]
        },
        {
          "id": "1.1.3",
          "name": "Child 1-3",
          "children": [

          ]
        }
      ]
    },
    {
      "id": "1.2",
      "name": "Child 2",
      "children": [
        {
          "id": "1.2.1",
          "name": "Child 2-2",
          "children": [

          ]
        }
      ]
    }
  ]
}

这是作为响应的 JSON 字符串。必须递归地获取父元素的所有父 ID。

例如，输入是 1.2.1 然后它返回 [1.2] 输入为 1.1.3 然后返回 [1.1, 1]

我怎样才能做到这一点？

【问题讨论】：

请展示您的尝试。如果你还没有尝试过任何东西，你应该这样做。如果没有体面的尝试，您就是客户。没有人是为客户而来的。
@user630209 你能解释一下逻辑吗，据我所知，如果你必须得到所有父母的身份证，那么如果你的输入是 1.2.1 那么输出应该是 [1.2, 1] , 如果我错了，请纠正我。
看看this。

标签： javascript json angular

【解决方案1】：

只是一个使用 dfs 的简单递归

const data = JSON.parse('{"id":"1","name":"root","children":[{"id":"1.1","name":"Child 1","children":[{"id":"1.1.1","name":"Child 1-1","children":[{"id":"1-1-1","name":"Child 1-1-1","children":[]}]},{"id":"1.1.2","name":"Child 1-2","children":[]},{"id":"1.1.3","name":"Child 1-3","children":[]}]},{"id":"1.2","name":"Child 2","children":[{"id":"1.2.1","name":"Child 2-2","children":[]}]}]}')

function dfs (target, node) {
  if (node.id === target) { return node.id }
  if (!node.children) { return false } // we could even skip that line since in your data you seem to have an empty array
  const has = node.children.find(c => dfs(target, c))
  return has && [node.id].concat(has.id)
}
console.log(dfs('1.2.1', data))
console.log(dfs('1.1.3', data))

【讨论】：

【解决方案2】：

您可以采用迭代和递归的方法，并且

chcek 如果给定的数据不是对象，则返回
检查id，如果找到则返回一个空数组，由调用函数填充
迭代children，发现短路并再次调用该函数。

function getParentIds(object, id) {
    var ids;
    if (!object || typeof object !== 'object') return;          // no object
    if (object.id === id) return [];                            // id found
    return object.children.some(o => ids = getParentIds(o, id)) // call recursive function
        ? [...ids, object.id]                                   // if found, take ids
        : undefined;                                            // otherwise return falsy
}

var data = { id: "1", name: "root", children: [{ id: "1.1", name: "Child 1", children: [{ id: "1.1.1", name: "Child 1-1", children: [{ id: "1-1-1", name: "Child 1-1-1", children: [] }] }, { id: "1.1.2", name: "Child 1-2", children: [] }, { id: "1.1.3", name: "Child 1-3", children: [] }] }, { id: "1.2", name: "Child 2", children: [{ id: "1.2.1", name: "Child 2-2", children: [] }] }] };

console.log(getParentIds(data, '1.2.1')); // ['1.2']
console.log(getParentIds(data, '1.1.3')); // ['1.1', '1']
console.log(getParentIds(data, 'foo'));   // undefined

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【讨论】：

【解决方案3】：

您必须解析完整的对象以递归地将父 id 注入子对象。这样的事情会做的事情。

function injectParents(data, parents) {
    if(!parents) {
        parents = [];
    }
    parents.push(data.id);
    data.children.map(child=>{
        child.parents = parents;
        if(child.children && child.children.length>0) {
            child = injectParents(child, Array.from(parents));
        }
        return child;
        });
    return data;    
}

那么你通常会这样称呼它

const injectedResponse = injectParents(response, null);

【讨论】：

【解决方案4】：

你可以使用

for(let x in arrayName){
   //here you can access the json 
   console.log(arayName(x).id)
}

【讨论】：

【解决方案5】：

这就是你要找的东西吗？

//Input
let input = '1.2.1';

//Data
data = JSON.parse('{"id":"1","name":"root","children":[{"id":"1.1","name":"Child 1","children":[{"id":"1.1.1","name":"Child 1-1","children":[{"id":"1-1-1","name":"Child 1-1-1","children":[]}]},{"id":"1.1.2","name":"Child 1-2","children":[]},{"id":"1.1.3","name":"Child 1-3","children":[]}]},{"id":"1.2","name":"Child 2","children":[{"id":"1.2.1","name":"Child 2-2","children":[]}]}]}')

//Main function start here
function findIdWhereChild(data, input) {
  if (data.children?.find(x => x.id == input)) {
    return data.id;
  }
  else {
    if (data.children.length > 0) {
      for (let i = 0; i < data.children.length; i++) {
        let findalResult = findIdWhereChild(data.children[i], input);
        if (findalResult) {
          return findalResult;
        };
      };

    } else {
      return undefined;
    }
  }
};

//Execution LOGs
console.log(findIdWhereChild(data, input));

【讨论】：