splice js remove code example

Example 1: add element to array using splice

//we can add elements to array using splice

const strings=['a','b','c','d']

//go the 2nd index,remove 0 elements and then add 'alien' to it
strings.splice(2,0,'alien')

console.log(strings) //["a", "b", "alien", "c", "d"]

//what is the time complexity ???
//worst case is O(n). if we are adding to end of array then O(1)
//in our example we added to the middle of array so O(n/2)=>O(n)

Example 2: array.splice javascript

const months = ['Jan', 'March', 'April', 'June'];
months.splice(1, 0, 'Feb');
// inserts at index 1
console.log(months);
// expected output: Array ["Jan", "Feb", "March", "April", "June"]

months.splice(4, 1, 'May');
// replaces 1 element at index 4
console.log(months);
// expected output: Array ["Jan", "Feb", "March", "April", "May"]

months.splice(0, 1);
// removes 1 element at index 0
console.log(months);
// expected output: Array ["Feb", "March", "April", "May"]

Example 3: splice method js

let myFish = ['angel', 'clown', 'mandarin', 'sturgeon']
//insert new element into array at index 2
let removed = myFish.splice(2, 0, 'drum')

// myFish is ["angel", "clown", "drum", "mandarin", "sturgeon"] 
// removed is [], no elements removed

Example 4: remove element from array javascript

let numbers = [1,2,3,4]

// to remove last element
let last_num = numbers.pop();
// numbers will now be [1,2,3]

// to remove first element
let first_num = numbers.shift();
//numbers will now be [2,3]

// to remove at an index
let number_index = 1
let index_num = numbers.splice(number_index,1); //removes 1 element at index 1
//numbers will now be [2]

//these methods will modify the numbers array and return the removed element