The JavaScript Array object lets you store multiple values in a single variable. An array is used to store a sequential collection of multiple elements of same or different data types. In JavaScript, arrays are dynamic, so you don’t need to specify the length of the array while defining the array. The size of a JavaScript array may decrease or increase after its creation. 

Basic Terminologies of JavaScript Array

• Array: A data structure in JavaScript that allows you to store multiple values in a single variable.

• Array Element: Each value within an array is called an element. Elements are accessed by their index.

• Array Index: A numeric representation that indicates the position of an element in the array. JavaScript arrays wordpress widgets for blog are zero-indexed, meaning the first element is at index 0.

• Array Length: The number of elements in an array. It can be retrieved using the length property.

JavaScript splice() method

The splice() method adds/removes items to/from an array, and returns the removed item(s). This method changes the original array.

array.splice(index, howmany, item1, ….., itemX)

index (Required) — An integer that specifies at what position to add/remove items, Use negative values to specify the position from the end of the array

howmany (Optional) — The number of items to be removed. If set to 0, no items will be removed

item1, …, itemX (Optional) — The new item(s) to be added to the array

var fruits = [“Banana”, “Orange”, “Apple”, “Mango”];
fruits.splice(2, 0, “Lemon”, “Kiwi”);

Output: Array [ “Banana”, “Orange”, “Lemon”, “Kiwi”, “Apple”, “Mango” ]

JavaScript slice() method

The slice() method returns the selected elements in an array, as a new array object. The slice() method selects the elements starting at the given start argument, and ends at, but does not include, the given end argument. The original array will not be changed.

array.slice(start, end)

start (Optional) — An integer that specifies where to start the selection (The first element has an index of 0). Use negative numbers to select from the end of an array. If omitted, it acts like “0”.

end (Optional) — An integer that specifies where to end the selection. If omitted, all elements from the start position and to the end of the array will be selected. Use negative numbers to javascript example for beginners select from the end of an array.

var fruits = [“Banana”, “Orange”, “Lemon”, “Apple”, “Mango”];
var citrus = fruits.slice(1, 3);

Output: Array [ “Orange”, “Lemon” ]

var fruits = [“Banana”, “Orange”, “Lemon”, “Apple”, “Mango”];
var citrus = fruits.slice(1, 4);

Output: Array [ “Orange”, “Lemon”, “Apple” ]