移除與數組值相等的物件的操作

Question

我有一個物件數組和一個普通數組，如果物件數組中的項等於普通數組中的項，我想要移除它。對我來說這很困惑。

以下是我目前嘗試過的：

<code>var countries =
[
{ChoicesID: 1, ChoicesName : 'afghanistan'},
{ChoicesID: 2, ChoicesName : 'albania'},
{ChoicesID: 3, ChoicesName : 'algeria'},
{ChoicesID: 4, ChoicesName : 'angola'},
{ChoicesID: 5, ChoicesName : 'argentina'},
{ChoicesID: 6, ChoicesName : 'armenia'}
];

var answer = ['afghanistan','albania','algeria'];

var ChoicesName = new Set(countries.map(d => d.ChoicesName));
var NewCountries = [...ChoicesName, ...answer.filter(d => !ChoicesName.has(countries.find(o => o.ChoicesName === answer)))];
console.log(NewCountries );</code>

預期輸出應該是這樣的：

var NewCountries =
     [
       {ChoicesID: 4, ChoicesName : 'angola'},
       {ChoicesID: 5, ChoicesName : 'argentina'},
       {ChoicesID: 6, ChoicesName : 'armenia'}
     ];

Answer 1

var countries = 
[
{ChoicesID: 1, ChoicesName : '阿富汗'},
{ChoicesID: 2, ChoicesName : '阿尔巴尼亚'},
{ChoicesID: 3, ChoicesName : '阿尔及利亚'},
{ChoicesID: 4, ChoicesName : '安哥拉'},
{ChoicesID: 5, ChoicesName : '阿根廷'},
{ChoicesID: 6, ChoicesName : '亚美尼亚'}
];

var answer = ['阿富汗','阿尔巴尼亚','阿尔及利亚'];

var NewCountries = countries.filter(o => !answer.includes(o.ChoicesName))

console.log(NewCountries)

像這樣？

Answer 2

使用 filter 並刪除如果 answer# 中存​​在它。建立一個answerSet 以進行O(1) 的查找，否則可以使用includes，但includes 的時間複雜度為O(m)（其中m 是answer 陣列中的元素數量，n 是countries 陣列中的元素數量）

使用 set
O(m) O(n).O(1) = O(n)（給定 n>m）

使用 includes
O(n).O(m) = O(nm)

var countries = [{ChoicesID: 1, ChoicesName : 'afghanistan'},{ChoicesID: 2, ChoicesName : 'albania'},{ChoicesID: 3, ChoicesName : 'algeria'},{ChoicesID: 4, ChoicesName : 'angola'},{ChoicesID: 5, ChoicesName : 'argentina'},{ChoicesID: 6, ChoicesName : 'armenia'}];
var answer = ['afghanistan','albania','algeria'];

const answerSet = new Set(answer)

const newCountries = countries.filter(c => !answerSet.has(c.ChoicesName))

console.log(newCountries)