splice element from array javascript code example

Example 1: how to take an element out of an array in javascript

var data = [1, 2, 3];

// remove a specific value
// splice(starting index, how many values to remove);
data = data.splice(1, 1);
// data = [1, 3];

// remove last element
data = data.pop();
// data = [1, 2];

Example 2: add elements to middle of array using splice

//we can add elements to middle of  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 3: splice javascritp

let colors = ['red', 'blue', 'green'];

let index_element_to_be_delete = colors.indexOf('green');

colors.splice(index_element_to_be_delete); 

//Colors now: ['red', 'blue']

Example 4: 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 5: Array#splice

let arrDeletedItems = array.splice(start[, deleteCount[, item1[, item2[, ...]]]])

Example 6: splice from array

let myFish = ['angel', 'clown', 'mandarin', 'sturgeon']
let removed = myFish.splice(2, 0, 'drum')

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