How to remove duplicates from the array of array in javascript?-CodePudding

I have an array let arr = [ ['A1', 'B2'], ['B1', 'A1'], ['A2','B1'], ['A1', 'B1']]. Which has duplicate ['B1', 'A1'] and ['A1', 'B1'] of different direction still it should be removed and expected output should be [ ['A1', 'B2'], ['B1', 'A1'], ['A2','B1']]. Please help me in this, thanks in advanced.

CodePudding user response：

You could filter with a Set with normalized values (sorted and joined).

const
    getValue = ([...a]) => a.sort().join(),
    array = [['A1', 'B2'], ['B1', 'A1'], ['A2', 'B1'], ['A1', 'B1']],
    result = array.filter((s => a => (v => !s.has(v) && s.add(v))(getValue(a)))(new Set));

console.log(result);

CodePudding user response：

function removeRepeatedArray(arrays){
 const map = new Map();
 
 for(let i = 0; i < arrays.length; i  ){
   // convert each array to a unique key 
   // subarrays needs to be sorted first
   const key = arrays[i].sort().join("");
 
   if(map.has(key)){
     // if exists replace it with undefined
     // you can use splice method to remove the repeated array it index i
     // I am using filter to keep the logic simple
     // using splice will require updating i
     arrays[i] = undefined;
   }else{
     map.set(key, arrays[i])   
   }
 }

  return arrays.filter(el => el !== undefined);
}

CodePudding user response：

You can use Array.reduce() to get the required result, for each element in the input array we create a key.

We'll use this key to create an entry in a map object, and duplicate items will be eliminated since they will share the same key.

Once we have all items in our map, we'll use Object.values() to get the resulting (unique) array.

let arr = [ ['A1', 'B2'], ['B1', 'A1'], ['A2','B1'], ['A1', 'B1']]

const result = Object.values(arr.reduce((acc, el) => {
    // Create a key based on what we consider a duplicate.
    let key = el.sort().join("-");
    acc[key] = acc[key] || el;
    return acc;
}, {}));

console.log('Result:', result)

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Another approach is to use the lodash function uniqBy using the iteratee el => el.sort().join('-'):

let arr = [ ['A1', 'B2'], ['B1', 'A1'], ['A2','B1'], ['A1', 'B1']]

const result = _.uniqBy(arr, el => el.sort().join('-'));
console.log('Result:', result)

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