Remove elements from an array according to empty elements of another array

Question

I want to remove elements from an array only if exist empty elements in another array. I have this:

var fruits = ["Banana", "Naranja", "Manzana", "Mango", "Fresa", "Limón", "Lima", "Sandia"];
var vegetales = ["", "Ajo", "", "Cebolla", "Tomate", "", "", "Zanahoria"];
 
// The output should be this:
// ["Naranja", "Mango", "Fresa", "Sandia"]
function myFunction() {
 for (var i in vegetales) {
 if (vegetales[i] == '') {
 frutaAeliminar = fruits[i];
 indexFruta = fruits.indexOf(frutaAeliminar);
 if (indexFruta != -1) {
 fruits.splice(indexFruta, 1)
 }
 }
 }
 console.log(fruits);
}
myFunction();

Answer 1

Example using ES6

Use Array.filter and using && in a ternary allows us to not bother with else if it's not needed

const fruits = ["Banana", "Naranja", "Manzana", "Mango", "Fresa", "Limón", "Lima", "Sandia"];
const vegetales = ["", "Ajo", "", "Cebolla", "Tomate", "", "", "Zanahoria"];
/* only pick if corresponding array item does not equal '' */ 
const newArray = fruits.filter((fruit, idx) => (vegetales[idx] !== '' && fruit))
console.log(newArray)

Answer 2

You could filter with the truthy value of the corresponding vegetales item.

var fruits = ["Banana", "Naranja", "Manzana", "Mango", "Fresa", "Limón", "Lima", "Sandia"];
 vegetales = ["", "Ajo", "", "Cebolla", "Tomate", "", "", "Zanahoria"],
 newArray = fruits.filter((_, i) => vegetales[i]);
console.log(newArray)

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Answer 3

I think you're getting mixed up because you're changing the length of the array while looping through it. This solution uses a third array to push results to w/o changing the original arrays.

Also, a few quick reminders:

1. Use for...in only for iterating over object key/value pairs-- otherwise use a standard for loop.
2. Don't forget to declare your variables w/ a var statement --otherwise you're going to pollute the global namespace.

var fruits = ["Banana", "Naranja", "Manzana", "Mango", "Fresa", "Limón", "Lima", "Sandia"];
var vegetales = ["", "Ajo", "", "Cebolla", "Tomate", "", "", "Zanahoria"];
var i;
var outputArr = [];
// The output should be this:
// ["Naranja", "Mango", "Fresa", "Sandia"]
function myFunction() {
 for (i=0; i<vegetales.length; i++) {
 if (vegetales[i] !== '') {
 outputArr.push(fruits[i]);
 }
 }
 console.log(outputArr);
}
myFunction();

Answer 4

Simple solution:

var fruits = ["Banana", "Naranja", "Manzana", "Mango", "Fresa", "Limón", "Lima", "Sandia"];
var vegetales = ["", "Ajo", "", "Cebolla", "Tomate", "", "", "Zanahoria"];
var result = [];
for(var i = 0;i<fruits.length;i++){
 if(vegetales[i]!=""){
 result.push(fruits[i]);
 }
}
console.log(result);

Output:

["Naranja", "Mango", "Fresa", "Sandia"]

Run here:

var fruits = ["Banana", "Naranja", "Manzana", "Mango", "Fresa", "Limón", "Lima", "Sandia"];
var vegetales = ["", "Ajo", "", "Cebolla", "Tomate", "", "", "Zanahoria"];
var result = [];
for(var i = 0;i<fruits.length;i++){
	if(vegetales[i]!=""){
		result.push(fruits[i]);
	}
}
console.log(result);

N.B.: Modification can be made.