Question 50574 in Javascript Question posted in
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remove object array if equal to value of array – Javascript

i have a object array and a normal array, i want to remove item in object array if it is equal to my normal array. it is confusing for me to do.

Here’s what i have tried so far

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 );

The expected output should be like this

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

3

Answers


  1. 0

    use filter and remove if the answer has it. created an answerSet to get O(1) lookup otherwise can use includes but includes is O(m) (m is no of elements in the answer array, n is elements in countries array)

    with set
    O(m) + O(n).O(1) = O(n) (given n>m)

    with 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)
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  2. 0 
    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 NewCountries = countries.filter(o => !answer.includes(o.ChoicesName))

console.log(NewCountries)

    like this?

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  3. 0 
    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 filteredArray = countries.filter(
    (country) => !answer.includes(country.ChoicesName)
  );
  console.log(filteredArray);
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