CODEWITHSUNDEEP
javascriptarraysecmascript-6angular6
Ahsan Alam Siddiqui
Ahsan Alam Siddiqui

Reputation: 71

How to remove array from an array in javascript (Angular6)?

I have this array

var a = [[1,3][2,3],[3,4],[6,7]];
var b =[[1,3],[2,3]];

I want to remove b array from a.

I tried it 

var arr = [[1,3],[2,3]];
var b = [1,3];
var arr = arr.filter((el)=> !b.includes(el));
console.log(arr);

but it is returning the same array "arr". It's not removing the array "b" form array "arr".

Upvotes: 2

Views: 76

Answers (4)

Nikhil Aggarwal
Nikhil Aggarwal

Reputation: 28455

In case of simplistic use case, where the order of items, number of items, value of items will be same you can try following

var a = [[1,3], [2,3]];
var b =[1,3];
a = a.filter(v=> v.join() !== b.join());
console.log(a);

If you want to consider order, number and value, please try following

var a = [[1,3], [2,3]];
var b =[1,3];
// Create a map where key is item and value is its occurence
let bObj = b.reduce((ac, c) => Object.assign(ac, {[c]: (ac[c] || 0) + 1}), {});
a = a.filter(v=> {
  // For every value, create a copy of bObj
  let temp = {...bObj};
  // for every value in item, decrements the value by 1
  v.forEach(e => temp[e] = (temp[e] || 0) - 1);
  // Get all the values of object
  let tempValues = Object.values(temp);
  // If all values are 0, then it is an exact match, return false else return true
  if(new Set(tempValues).size === 1 && tempValues[0] === 0) return false;
  return true;
});
console.log(a);

EDIT

var a = [[1,3],[2,3],[3,4],[6,7]];
var b = [[1,3],[2,3]];
// Create a map where key is item and value is its occurence
let bObj = b.map(v => v.reduce((ac, c) => Object.assign(ac, {[c]: (ac[c] || 0) + 1}), {}));
a = a.filter(v=> {
  // For every value, create a copy of bObj
  let temp = JSON.parse(JSON.stringify(bObj));
  // for every value in item, decrements the value by 1
  v.forEach(e => temp.forEach(t => t[e] = (t[e] || 0) - 1));
  return !temp.some(t => {
    // Get all the values of object
    let tempValues = Object.values(t);
    // If all values are 0, then it is an exact match, return false else return true
    return (new Set(tempValues).size === 1 && tempValues[0] === 0)
  });
});
console.log(a);

Upvotes: 4

user8851697
user8851697

Reputation: 41

var my_array = ["raj","bob","clreak","kevin","dJ"];
var start_index = 0
var number_of_elements_to_remove = 1;
var removed_elements = my_array.splice(start_index, number_of_elements_to_remove);

Upvotes: 0

Ankit Agarwal
Ankit Agarwal

Reputation: 30739

You can first find the index on arr that you want to remove using every() operation then splice() it:

var arr = [[1,3],[2,3]];
var b = [1,3];
var index = arr.findIndex(item => item.every(elem => b.includes(elem)));
arr.splice(index,1);
console.log(arr);

Upvotes: 0

Nina Scholz
Nina Scholz

Reputation: 386604

You could search fr the index by stringify the inner array and check against the strigified array b. Then check the index and splice.

var a = [[1, 3], [2, 3]],
    b = [1, 3],
    index = a.findIndex(
        (json => inner => JSON.stringify(inner) === json)
        (JSON.stringify(b))
    );
    
if (index !== -1) {
    a.splice(index, 1);
}

console.log(a);

Upvotes: 0

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