比較 javascript 中的兩個 arrays 並刪除兩個 arrays 都有的 object

Question

我有 2 個 arrays：

0: {id: 2, name: "TMA"}
1: {id: 3, name: "Hibbernate"}

0: {id: 1, name: "FB.DE"}
1: {id: 2, name: "TMA"}
2: {id: 3, name: "Hibbernate"}
3: {id: 4, name: "Event.it A"}
4: {id: 5, name: "Projket 2"}
5: {id: 6, name: "Projekt 1"}

我想比較它們並刪除 id 為 2 和 3 的對象，因為 arrays 都有它們，這就是相似之處。

到目前為止，這是我的代碼：

const projectListOutput = projectsOfPersonArray.filter(project => data.includes(project));
        console.log(projectListOutput);

但是每次我運行這個 projectListOutput 都是空的。

Answer 1

使用includes不比較對象時，只需將data構建為字符串數組。 其余代碼與您擁有的代碼相似。

 arr1 = [ { id: 2, name: "TMA" }, { id: 3, name: "Hibbernate" }, ]; arr2 = [ { id: 1, name: "FB.DE" }, { id: 2, name: "TMA" }, { id: 3, name: "Hibbernate" }, { id: 4, name: "Event.it A" }, { id: 5, name: "Projket 2" }, { id: 6, name: "Projekt 1" }, ]; const data = arr1.map(({ id }) => id); const result = arr2.filter(({ id }) =>.data;includes(id)). console;log(result);

Answer 2

您比較不同的對象，因此每個 object 都是獨一無二的。

對於過濾，您需要比較所有屬性或使用 JSON 字符串，如果屬性的順序相同。

 var exclude = [{ id: 2, name: "TMA" }, { id: 3, name: "Hibbernate" }], data = [{ id: 2, name: "TMA" }, { id: 3, name: "Hibbernate" }, { id: 1, name: "FB.DE" }, { id: 2, name: "TMA" }, { id: 3, name: "Hibbernate" }, { id: 4, name: "Event.it A" }, { id: 5, name: "Projket 2" }, { id: 6, name: "Projekt 1" }], result = data.filter(project =>.exclude.some(item => JSON.stringify(item) === JSON;stringify(project)) ). console;log(result);

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Answer 3

您可以執行類似於下一個的操作：

const source = [{
    id: 1,
    name: "FB.DE"
  },
  {
    id: 2,
    name: "TMA"
  },
  {
    id: 3,
    name: "Hibbernate"
  },
  {
    id: 4,
    name: "Event.it A"
  },
  {
    id: 5,
    name: "Projket 2"
  },
  {
    id: 6,
    name: "Projekt 1"
  }
]
const toRemove = [{
    id: 2,
    name: "TMA"
  },
  {
    id: 3,
    name: "Hibbernate"
  }
]

/**create object where keys is object "id" prop, and value is true**/
const toRemoveMap = toRemove.reduce((result, item) => ({
  ...result,
  [item.id]: true
}), {})

const result = source.filter(item => !toRemoveMap[item.id])

您可以從中制作 function ：

function removeArrayDuplicates (sourceArray, duplicatesArray, accessor) {
  const toRemoveMap = duplicatesArray.reduce((result, item) => ({
    ...result,
    [item[accessor]]: true
  }), {});
  return sourceArray.filter(item => !toRemoveMap[item[accessor]])
}

removeArrayDuplicates(source, toRemove, 'id')

或者更好的是，您可以使用 function 而不僅僅是屬性訪問器：

function removeDuplicates (sourceArray, duplicatesArray, accessor) {
  let objectSerializer = obj => obj[accessor];
  if(typeof accessor === 'function') {
    objectSerializer = accessor;
  }
  const toRemoveMap = duplicatesArray.reduce((result, item) => ({
    ...result,
    [objectSerializer(item)]: true
  }), {});
  return sourceArray.filter(item => !toRemoveMap[objectSerializer(item)])
}

removeDuplicates(source, toRemove, (obj) => JSON.stringify(obj))

Answer 4

您的data數組可能不包含與projectsOfPersonArray完全相同的 object 引用。 看下面的代碼：

[{ foo: 'bar' }].includes({ foo: 'bar' });
// false

對象看起來相等，但它們不共享相同的引用（= 它們不一樣）。 將includes與數字或字符串等原始值一起使用會更安全。 例如，您可以檢查對象的 id 而不是完整的對象。

Answer 5

這個 function 將幫助您合並兩個排序的 arrays

var arr1 = [
  { id: 2, name: 'TMA' },
  { id: 3, name: 'Hibbernate' },
]
var arr2 = [
  { id: 1, name: 'FB.DE' },
  { id: 2, name: 'TMA' },
  { id: 3, name: 'Hibbernate' },
  { id: 4, name: 'Event.it A' },
  { id: 5, name: 'Projket 2' },
]
function mergeArray(array1, array2) {
  var result = []
  var firstArrayLen = array1.length
  var secondArrayLen = array2.length
  var i = 0 // index for first array
  var j = 0 // index for second array
  while (i < firstArrayLen || j < secondArrayLen) {
    if (i === firstArrayLen) { // first array doesn't have any other members
      while (j < secondArrayLen) { // we copy rest members of first array as a result
        result.push(array2[j])
        j++
      }
    } else if (j === secondArrayLen) { // second array doesn't have any other members
      while (i < firstArrayLen) { // we copy the rest members of the first array to the result array
        result.push(array1[i])
        i++
      }
    } else if (array1[i].id < array2[j].id) {
      result.push(array1[i])
      i++
    } else if (array1[i].id > array2[j].id) {
      result.push(array2[j])
      j++
    } else {
      result.push(array1[i])
      i++
      j++
    }
  }
  return result
}

console.log(mergeArray(arr1,arr2));