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hubman
Asked: 2020-01-07 20:22:51 +0800 CST 2020-01-07 20:22:51 +0800 CST

Initialize with a variable amount of the same elements in an array

  • 772

I want to fill a quantity, for example 9 elements of the array with the value of 0

let resultados = [];
    resultados[0] = 0;
    resultados[1] = 0;
    resultados[2] = 0;
    resultados[3] = 0;
    resultados[4] = 0;
    resultados[5] = 0;
    resultados[6] = 0;
    resultados[7] = 0;
    resultados[8] = 0;

I want to generalize it to fill n elements in the array, is there a proper js function to do this? or should I do it with a loop to fill it?

javascript

4 Answers

  1. The easiest way for me is the following:

    var len = ~~(Math.random() * 28);
console.log(`Array length will be ${len}`);
var array = new Array(len).fill(0);
console.log(array);

    where lenis the length of your array and 0is the default value you want.

    • 5
  2. Best Answer

    One way is how you do it, initialize all elements with value 0.

    But if you have created an array and regardless of the number of elements that your array contains, you can make a loop to modify the value of all its elements:

    for( i=0; i< resultados.length; i++){
   resultados[i] = 0;
}

    this way all the elements in your array would have the value of 0.

    If you have already created your Array and want to initialize its values , another way is to use the method fill(value, start, end)

    • value Value with which to fill the array.
    • start Initial index, default is 0.
    • final Final index, defaults to this.length.
    resultados.fill(0, 0, resultados.length)

    Example:

    var myArray = [1, 2, 3, 4, 5, 6, 7, 8];
var resultados = myArray.fill(0, 0, 9)
 
for(i = 0;i<resultados.length;i++){   
 console.log("valor en indice ["+i+"] " + resultados[i])  
}

    If you want to initially create your array containing 0 values , you can use the same fill() method like this:

    //Crea array con nueve elementos y asigna valor 0
var resultados = new Array(9).fill(0);

//verifica valores de elementos en array    
for(i = 0;i<resultados.length;i++){   
 console.log("valor en indice ["+i+"] " + resultados[i])  
}

    • 4

  3. This might help you:

    let resultados =new Array (0, 0, 0, 0, 0, 0, 0, 0, 0);

    It is a way of assigning the values ​​when creating it.

    • 1

  4. In javascript, if you assign 10 parameters to a function of which only 4 have a value and you are going to add them to an array, if the function is unique it will add 10 values ​​of which 4 have a value, but this is a method where the array is static.

    function llenarArray(param1, param2, param3, param4, param5, param6, param7, param8, param9, param10) {
  let resultados = new Array(param1, param2, param3, param4, param5, param6, param7, param8, param9, param10);
  return resultados;
}

console.log(llenarArray(1, 2, 3, 4, 5).toString());
console.log(llenarArray(1, 2, 3, 4, 5, null, null, null, null, null).toString());

    If what you want is a dynamic array, you can choose to enter the values ​​as a list, which requires a loop either inside the function or a loop calling the function, this last option is the most viable since your function just inputs a value and from where you call the function you control the size of the array.

    var array = [];

function llenarArray(valor) {
  array.push(valor)
}
llenarArray("1");
llenarArray("2");
llenarArray("3");
llenarArray("4");
console.log(array.toString())

    From outside the function filling the array.

    var array = [],
  size = 5;

function llenarArray(valor) {
  array.push(valor)
}
for (i = 0; i < size; i++) {
  llenarArray(i * 10);
}
console.log(array.toString())

    ECMASCRIPT 6

    One of the most convenient changes is the possibility of defining an indeterminate number of parameters in assignment instructions, either as a function parameter or as a variable definition.

    function llenarArray(...candidates) { // candidates contains the rest of arguments passed
  let array = [...candidates]
  return array;
}

let result = llenarArray("banana", "apple","kiwi");

console.log(result); // ["banana", "apple", "kiwi", "watermelon", "strawberry"]

    • 1