Working with Array Elements

Let's explore how to

Modify array elements;
Find the length of an array;
Access the last element and delve deeper into the concept of indexing.

Modifying Array Elements

Array elements can be changed by accessing them through their index and assigning a new value.


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const weekdays = ["Monday", "Tuesday", "Wednesday"];
weekdays[0] = "Lunes";
weekdays[1] = "Martes";

console.log(weekdays); // Output: Lunes, Martes, Wednesday

Here, we modify the first two elements of the weekdays array to their Spanish translations.

Array Length

The length property of an array represents the number of elements it contains. This property is dynamic and automatically adjusts when elements are added or removed.


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const mountains = ["Everest", "K2", "Kangchenjunga", "Lhotse"];

console.log(mountains.length); // Output: 4

In this example, the mountains array contains four elements, and mountains.length returns 4.

Finding the Last Element

To retrieve the value of the last element in an array, we can calculate its index using the array's length. The index of the last element is always array.length - 1.


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const vehicles = ["car", "bike", "bus", "train"];
const lastIndex = vehicles.length - 1;

console.log(vehicles[lastIndex]); // Output: train

In this case, lastIndex is computed as 3, which is the index of the last element, and we access the last element using vehicles[lastIndex].

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Seção 4. Capítulo 3