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gmarsi
Asked: 2020-10-01 10:07:32 +0800 CST 2020-10-01 10:07:32 +0800 CST

Remove duplicate elements from an array

  • 772

Please read the question before marking it as repeated, thanks.

What I need is that if there are duplicate elements in the array, remove them all. The array is something similar to this:

var array = [[1,2],
             [2,3], // repetido
             [3,4],
             [4,5],
             [2,3], // repetido
             [5,6],
             [6,7], // repetido
             [6,7], // repetido
             [7,8]]

so it would be like this:

var array = [[1,2],
            [3,4],
            [4,5],
            [5,6],
            [7,8]]

In the array there can be a minimum of 1000 values, so nesting a for loop in another, and checking value by value is not efficient, the browser closes and the processor is set to 90%

javascript

2 Answers

  1. Best Answer

    The iteration of the Array must occur only 1 time, for each iterated element we must evaluate in a new one arrayif it already exists or not.

    The explanation is in the code, the functions used are some() to verify that it exists or not in the array, and splice() to remove arrayduplicate elements.

    var array = [[1,2],[2,3],[3,4],[4,5],[2,3], [5,6],[6,7], [6,7], [7,8]]
let newArray = [];
array.forEach(elem=>{
  // verificamos si existe en el nuevo array , comparando su dos componentes
  // posición 0 y 1 , si no existe, añadimos el emenento al array
  if(!newArray.some(valor=> valor[0] === elem[0] && valor[1] === elem[1]))  
     newArray.push(elem);
  else {
	//caso contrario buscamos las coincidencias para eliminarlas
     newArray.forEach((valor,index)=> {
	//iteramos el array de no duplicados y eliminamos
	//los valores. con splice 
	if(valor[0]=== elem[0] && valor[1] === elem[1]) newArray.splice(index,1);
     });
  }
})
console.log(newArray);

    • 1

  2. You can try this:

    var array = [[1,2],
             [2,3], // repetido
             [3,4],
             [4,5],
             [2,3], // repetido
             [5,6],
             [6,7], // repetido
             [6,7], // repetido
             [7,8]];
             
const eliminarRepetidos = (array) => {
    var unicos = [];
    var itemsEncontrados = {};
    for(var i = 0, l = array.length; i < l; i++) {
        var stringified = JSON.stringify(array[i]);
        if(itemsEncontrados[stringified]) { continue; }
        unicos.push(array[i]);
        itemsEncontrados[stringified] = true;
    }
    return unicos;
}

let arrayFiltrado = eliminarRepetidos(array);
console.log(arrayFiltrado);

    The easiest way I could think of was to serialize the array value and store if it was already found. Font

    • 0