Question

我该如何按值获取密钥？

这是我的代码。

function getkey(obj, key) {
  for (i = 0; i < obj.length; i++) {
    if (obj[i] === key) {
      return obj[i];
    }
  }
}
var json = {
  test: {
    "key1": {
      "inkey1": "value1",
      "inkey2": "value2"
    },
    "key2": {
      "inkey3": "value3",
      "inkey4": "value4"
    }
  }
}
console.log(getkey(json, "value2"));

我想按值2获取key1 我如何获得key1？

请帮助我！

Answer 1

有许多方法可以做到这一点，一种方法是对函数使用变体并应用递归。请参见下面的代码段：

function getkey(obj, key) {
  for (i = 0; i < Object.keys(obj).length; i++) {
    if (Object.values(obj)[i] === key) {
      return Object.keys(obj)[i];
    }
    if (Object.values(obj)[i].constructor == Object) {
      return getkey(Object.values(obj)[i], key)
    }
  }
}
var json = {
  test: {
    "key1": {
      "inkey1": "value1",
      "inkey2": "value2"
    },
    "key2": {
      "inkey3": "value3",
      "inkey4": "value4"
    }
  }
}
console.log(getkey(json, "value2"));

结果为inkey2。无论键在对象中嵌套的深度如何，此方法都应起作用。

Answer 2

对于非嵌套版本

function getKeyByValue(obj, value) {
  for (let key in obj) {
     for (let inkey in obj[key]) {
       if (obj[key][inkey] === value) {
         return key;
       }
     }
  }
}

console.log(getKeyByValue(json['test'], "value2")); //key1

对于您不知道对象有多深的嵌套版本

function getKeyByValue(obj, value, path) {
  path = path ? path + '.' : '';
  for (let key in obj) {
    if (obj.hasOwnProperty(key)) {
      if (obj[key] === value) {
        return path + key;
      } else if (typeof obj[key] === 'object') {
        let found = getKeyByValue(obj[key], value, path + key);
        if (found) {
            return found;
        }
      }
    }
  }
}

console.log(getKeyByValue(json, "value2")); //"test.key1.inkey2"

我怎样才能通过价值获得钥匙？

2 个答案: