使用 lodash（或 vanilla javascript）对对象数组进行排序和过滤

Question

我有这个对象，我想通过只保留对象的 2 个最高值来排序和过滤。

obj={ A :[{
      asset: 9,
      biodiversity: 4,
      infrastructure: 15,
      deflation: 11,
      energy: 9
    }],
  B:[{
      asset: 12,
      biodiversity: 10,
      infrastructure: 9,
      deflation: 7,
      energy: 15
    }],
  C:[{
      asset: 2,
      biodiversity: 12,
      infrastructure: 6,
      deflation: 6,
      energy: 8
    }]}

我想按对象的值对对象进行排序并过滤掉 2 个最高值，例如：

{A :[{
      infrastructure: 15,
      deflation: 11
    }],
  B:[{
      energy: 15,
      asset: 12
    }],
  C:[{
      biodiversity: 12,
      energy: 8
    }]}

我试过这个排序：

Object.keys(obj).forEach((a) => _.sortBy(obj[a][0])))

但这显然是错误的。 我正在使用 lodash，但也会接受 vanilla javascript 解决方案。

Answer 1

您可以获取内部对象的条目并按值降序排序，获取前两个键/值对并从中构建一个新对象。

 const data = { A: [{ asset: 9, biodiversity: 4, infrastructure: 15, deflation: 11, energy: 9 }], B: [{ asset: 12, biodiversity: 10, infrastructure: 9, deflation: 7, nergy: 15 }], C: [{ asset: 2, biodiversity: 12, infrastructure: 6, deflation: 6, energy: 8 }]}, result = Object.fromEntries(Object .entries(data) .map(([k, a]) => [k, a.map(o => Object.fromEntries(Object .entries(o) .sort((a, b) => b[1] - a[1]) .slice(0, 2) ))]) ); console.log(result);

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Answer 2

（编辑/注意：这是基于您最初发布的代码。我很高兴看到您更新了您的问题并摆脱了包装数组。）

这是一个相对实用的方法。

secondLargestValue函数在每个对象中查找阈值。 copyWithoutValsBelowThreshold函数为我们提供了对象的修改副本。

我们循环遍历顶级对象中的条目并应用这两个函数。 有关进一步说明，请参阅代码中的注释。

 let json = getArray(); // Identifies the original array // Defines `secondLargestVal` function const secondLargestVal = someObj => // Gets second item of array after sorting numerically in descending order Object.values(someObj).sort((a, b) => b - a)[1]; // Defines `copyWithoutValsBelowThreshold` function const copyWithoutValsBelowThreshold = ( (someObj, threshold) => { // This function doesn't mutate the original value clone = Object.assign({}, someObj); // Copies obj for(let prop in clone){ // Loops through properties, deleting non-qualifying ones if(clone[prop] < threshold){ delete clone[prop]; } } return clone; }); // Defines our main function const mutateJson = () => { let entries = Object.entries(json[0]); entries = entries.map(entry => { // `entry[0]` is the property name (eg: 'A') -- we don't actually use this // `entry[1]` is the value (in this case, an array containing a single object) let obj = entry[1][0]; // Identifies the actual object const threshold = secondLargestVal(obj); // Identifies minimum value // Updates the entry, deleting properties whose values are too low entry[1][0] = copyWithoutValsBelowThreshold(obj, threshold); return entry; }); json[0] = Object.fromEntries(entries); // Replaces the top-level object } // Calls the main function mutateJson(); console.log(json); // Provides the original array function getArray(){ return [{ A :[{ asset: 9, biodiversity: 4, infrastructure: 15, deflation: 11, energy: 9 }], B:[{ asset: 12, biodiversity: 10, infrastructure: 9, deflation: 7, energy: 15 }], C:[{ asset: 2, biodiversity: 12, infrastructure: 6, deflation: 6, energy: 8 }]}] }