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Accepted
Enzo Paez
Asked: 2022-03-19 06:25:34 +0800 CST 2022-03-19 06:25:34 +0800 CST

Check if element of an array is in another array

  • 772

I have 2 array one that has "Products" and another that has "productsExcluded".

I have to exclude the products that are in the "productsExcluded" array from the final list "Products" that is shown in a<option>

for(let i=0;i<$scope.productos.length;i++){
         
    $('#select-servicio').append($('<option value='+ $scope.productos[i].idProducto +' >' + $scope.productos[i].descripcion + '</option>'));
  
}

My idea was to go through them with 2 nested fors, but the array has more than 100,000 values, so it will be super inefficient.

javascript

2 Answers

  1. Use the method includes()inside the for so you only have one, as follows

    let myarray1 = ['hola','este','es','el','array','del','ciclo','for']
let myarray2 = ['lo', 'que','quieres','comparar','es']
for(let i=0;i<myarray1.length;i++){
    let element = myarray1[i]
    if(myarray2.includes(element)){
        console.log(`coincide '${element}'`)
    }
}

    in the part of console.log(${element})it you can replace it with a code that removes the excluded products from the products array

    • 2
  2. Best Answer

    How are you?

    Making use of includes(), filterand spread operator, you can achieve the filter, joining the products to be displayed in a select as follows:

    HTML

    <select id="select">
   <option selected="selected">Productos</option>
</select>

    JS

    let productos = ['uno','dos','tres','cuatro']
let excluidos = ['dos', 'cuatro','cinco','nueve']

let options = document.getElementById('select');

let filtro = [...productos,...excluidos.filter(p=> !productos.includes(p))]
filtro.forEach(items => {
  options.add(new Option(`${items}`));
});

    Spreat operator converts 2 arrays into a new one with the values ​​that filter() is responsible for returning, together with includes(), which verifies that the excluded array returns products that are not in the products array to generate the new array. Then the results are only iterated by inserting them into theselect>

    Cheers!

    • 1