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Franqo Balsamo
Asked: 2020-09-10 15:46:08 +0800 CST 2020-09-10 15:46:08 +0800 CST

Multiply elements of an Array

  • 772

I'm creating a function that takes an array of numbers and multiplies them but I haven't found a workable solution.

This is what I've gotten so far:

var total = 0;

var producto = [1,4,7];

function productoria(){
  for (var f=0;f<producto.lenght;f++){
    if(producto[f]!=0){
      total = total + (producto[f]*total);
    }
  }return total;
}
console.log(productoria());

javascript

5 Answers

  1. Using reduce()is really short:

    const producto = [1,4,7];

const res = producto.reduce((p,c)=>p*c);

console.log(res);

    MDN documentation with examples here . Basically reduce would work like this:

    arr.reduce(callback(acumulador, valorActual), valorInicial)

    Where the acumuladorstores the values ​​we want it to save when we want it to save them. The valorInicial, if not specified, takes the first value of the array (in this example: 1). In the case of multiplication, each iteration we are multiplying acumuladorthe value of each element, it would work as the totalquestion variable. The example without using the arrow function and using the return, would be:

    const producto = [1, 4, 7];

const res = producto.reduce(function (acumulador, valorActual){
    acumulador = acumulador * valorActual;
    return acumulador;
} );

console.log(res);

    The arrow function allows us to omit the returnand the {}. In this case, the final value is a single number, but we could define an object or an array as the initial value and operate on acumuladorit as we would with an object or an array.

    • 10
  2. Best Answer

    You have 3 errors:

    1. you got a guy inlength
    2. You need to initialize the variable totalto 1
    3. You don't need to add the total in each iteration

    It would be like this:

    var total = 1;

var producto = [1,4,7];

function productoria(){
  for (var f=0;f<producto.length;f++){
    if(producto[f]!=0){
      total = (producto[f]*total);
    }
  }return total;
}
console.log(productoria());

    • 9

  3. The producer is the multiplication of all the elements of the array, therefore it is not necessary to perform a sum, then the result is multiplied from 1.

    Another way to get the producer of an array is with a recursive method:

    var producto = [1,4,7];

function productoria(f){
  return f<producto.length ? producto[f]*productoria(f+1) : 1;
}

console.log(productoria(0));

    The code like this is much more simplified.

    I hope I have contributed to solve the problem, greetings.

    • 7

  4. In case you do not want to multiply by the number 0, I leave you a solution:

    const producto = [1,4,7,0];


let res = producto.filter(data => data !=0)
    .reduce((e, f) => e * f)



console.log(res);

    use filterbecause in your question you put an if condition that no number is equal to 0 -> if(producto[f]!=0){

    • 4

  5. let myArray = [1, 2, 5, 77, 99, 7, 6, 9]

    let multiplication = myArray.reduce((a, b)=> a * b) console.log(multiplication)

    • 0