How to use filter array to remove items in array?

Question

I have an array:

    var arr = [1,2,4,5,1,2,3,4,5];

And I have another array:

    var removeArr = [1,3,5];

I want it to remove elements in arr that has in the removeArr:

    var result = arr.filter(function(item){
                 return item != removeArr[???];
                 });

I have tried to iterate it using loop but it doesn't work.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes — Matt Burland, Apr 20 '17 at 17:33

score 2 · Answer 1 · answered Apr 20 '17 at 17:33

You can reach the desired output using Array#filter aswell as Array#indexOf functions.

var arr = [1,2,4,5,1,2,3,4,5],
    removeArr = [1,3,5],
    result = arr.filter(function(item){
      return removeArr.indexOf(item) == -1;
    });
    
    console.log(result);

score 2 · Answer 2 · answered Apr 20 '17 at 17:34

2

 var arr = [1,2,4,5,1,2,3,4,5];
 
 var removeArr = [1,3,5];
 
 var result = arr.filter(x => !removeArr.includes(x));
 
 console.log(result);

answered Apr 20 '17 at 17:34

Egor Stambakio

17,836
5
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score 2 · Answer 3 · answered Apr 20 '17 at 18:51

2

You could use a Set and test against while filtering.

var array = [1, 2, 4, 5, 1, 2, 3, 4, 5],
    removeArray = [1, 3, 5],
    result = array.filter((s => a => !s.has(a))(new Set(removeArray)));
    
console.log(result);

answered Apr 20 '17 at 18:51

Nina Scholz

376,160
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This is a clever one! Took some time to understand how it works, thanks for it. – Egor Stambakio Apr 20 '17 at 19:35
it uses a closure over a set. – Nina Scholz Apr 20 '17 at 19:36
Yes, I figured it out after rewriting into regular IIFE template. – Egor Stambakio Apr 20 '17 at 19:38

score 1 · Answer 4 · answered Apr 20 '17 at 17:33

1

var result = arr.filter(function(item){
    return removeArr.indexOf(item) === -1; // if the item is not included in removeArr, then return true (include it in the result array)
});

answered Apr 20 '17 at 17:33

ibrahim mahrir

31,174
5
48
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score 1 · Answer 5 · answered Apr 20 '17 at 17:35

1

You can check if a value is in an array by checking if the index of the item is not -1.

var result = arr.filter(item => removeArr.indexOf(item) === -1)

answered Apr 20 '17 at 17:35

claireinez

39
4

How to use filter array to remove items in array?

5 Answers5