Having the following array:
var arrayElementos = ["elemento 1" , "elemento 2" , "elemento 3"];
We apply the length property:
var arrayLargo = arrayElementos.length;
And doing alert(arrayLargo); returns 3.
I try to access the third element and it comes out:
alert (arrayLargo[3]);
undefined
Why, if there are 3 items, can I not access this third party?
This happens because in programming the indexes of arrays start to count always from 0 and not from 1 , that is:
//Número de elementos: 1 2 3
var arrayElementos = ["elemento 1" , "elemento 2" , "elemento 3"];
//Posición y/o indice: 0 1 2
console.log(arrayElementos[2])Obviously your fix has 3 elements , but its indices go from the number 0
You can always access the last element of an array by:
//Número de elementos: 1 2 3
var arrayElementos = ["elemento 1", "elemento 2", "elemento 3"];
//Posición y/o indice: 0 1 2
var length = arrayElementos.length; // 3
// 3 - 1 = 2
var ultimoElemento = arrayElementos[length - 1];
console.log(ultimoElemento);