public/subjects/3-directions

3 Directions

Accessing an array value [index]

Since numbers are not valid identifiers we can not use the . operator to access a value in an array, but we can use the [index] square brackets to access a value.

Example:

let numberList = [10, 20, 30, 40]
console.log(numberList[0]) // -> 10
console.log(numberList[3]) // -> 40
console.log(numberList[6]) // -> undefined

Since we start at 0, [0] will get the value at the first index.

note that if we try to access an element that doesn't exist we will get undefined as a value, just like non existing properties for an object.

Using the .length property

Another difference of the arrays is that they always keep track of how many elements are inside them.

You can use the .length property to get this value:

console.log([].length) // -> 0
console.log([1].length) // -> 1
console.log([1, 1, 1, 1].length) // -> 4

Instructions

We provide you a variable list that contains some elements, you will have to access them and assign their values to variables:

• a variable first of the first element of the list
• a variable last of the last element of the list
• a variable kiss of an array of 2 elements, the last and the first element of the list, in that order.

Example: if list is [1,2,3]

• first would be 1
• last would be 3
• kiss would be [3, 1]

🧑‍🎤 ............ Oh, ........... 🧑‍🎤
🎶 .. I wanna be last, yeah ... 🎶
🎵 . Baby let me be your last . 🎵
✨ ... Your last first kiss ... ✨
― One Direction