Commit 57ab3f2

In contrast to variables array can store _multiple values_. Each value in an array has an _index_ and each index has _a reference in a memory address_. Each value can be accessed by using their _indexes_. The index of an array starts from _zero_ and the last element is less by one from the length of the array.

Array is a collection of different data types which are ordered and changeable(modifiable). Allows duplicate element and different data types. An array can be empty or it may have different data type values

In JavaScript we can create array in different ways. Let us different ways to create an array.

As we have seen in earlier section, we can split a string at different position and we can change to an array. Let us see the examples blow.

We access each element in an array using their index. An array index start from 0. The picture below show clearly the starting of the index.

An array is mutable(modifiable). Once an array is created we can modify the contents or the array elements.

There are different methods to manipulate an array. These are some of the available methods to deal with arrays:_Array,length, concat, indexOf, slice, splice, join, toString, includes, lastIndexOf, isArray, fill, push, pop, shift, unshift_

const eightXvalues = Array(8).fill('X') // it creates eight element values

const eight0values = Array(8).fill(0) // it creates eight element values

const four4values = Array(4).fill(4) // it creates 4 element values

const fruitsAndVegetables = fruits.concat(vegetables)

console.log(numbers.length) // -> 5

Check an element if it exist in an array

lastIndexOf:Give the position of the last item in the array. If it exist it returns the index else it returns -1.

console.log(numbers.lastIndexOf(2)) // -7

join:To join the elements of the array, the argument passed in the join method will be joined in the array and return as a string. By default it joins with a comma but we can pass different string parameter which can be joined between the items.

Slice: To cut out a multiple items in range. It takes two parameters:starting and ending position. It doesn't include the ending position

Splice: It takes three parameters:Starting position, number of times to be removed and number items to be added.

Push: adding item in the end. To add item to the end of an existing array we use the push method

Pop: Removing item in the end

shift: Removing one array element in the beginning of the array

unshift: Adding array element in the beginning of the array

reverse: reverse the order of an array

sort: arrange array elements in ascending order. Sort takes a call back function, we wil see how we use sort with call back function in the coming sections.