arrays.js

// Arrays in javascript : collection of items
// Arrays is an special type of object
// Create Array
// An array is a special variable, which can hold more than one value:
// const cars = ["Saab", "Volvo", "BMW"];

// Example of syntax : 
// let marks = [97, 28, 37, 64, 57];
// console.log(marks);
// Output will be more define as position with length :
// (5) [97, 28, 37, 64, 57]

// Example with storing heroes names :
// let heroes = ["spiderman", "ironman", "thor", "hulk", "shaktiman",];
// console.log(heroes);


// Example with finding the length of arrays :
// let marks = [22, 29, 256, 54, 46 ];
// console.log(marks.length); //Property
// Output will be : 5

// console.log(typeof(marks));
// Output will be : 'object'
// Or in console we can find that type of array marks in an object : 'object'

// Array Indices : arr[0], arr[1], arr[2],.....
// An array is a special variable, which can hold more than one value:
// const cars = ["Saab", "Volvo", "BMW"];
// cars[0] in console
// Output will be : 0th term will be : Saab
// Arrays can be changed but strings cannot be changed as arrays are mutable & strings aren't mutable
// We can find the value of array via its position : 

// Example 1 :
// const marks = [29, 78, 63, 33, 47];
// console.log(marks[0]); // as this function can describe the 0th term of array 'marks'
// Output will be : 29

// Example 2 :
// console.log(marks[1]);
// Output will be : 78


// Looping over an array :
// Print all elements of an array
// let heroes = ["spiderman", "ironman", "thor", "hulk", "shaktiman"];

// Usually :
// console.log(heroes[0]);
// console.log(heroes[1]);
// console.log(heroes[2]);
// console.log(heroes[3]);
// Output : 
// arrays.js:51 spiderman
// arrays.js:51 ironman
// arrays.js:52 thor
// arrays.js:53 hulk


// Better pratice are loops : loops in Array
// Array length = last index + 1

// Example 1 : for printing all elements in an array: 
// let arr = [1, 2, 3, 4, 5];

// for loop
// for(let index = 0; index<arr.length ; index++){
//     console.log(arr[index]);
// }
// Output will be : 
// 1
// 2
// 3
// 4
// 5

// For of loop
// for(let num of arr){
//     console.log(num);
// }
// Output
// 1
// 2
// 3
// 4
// 5

// Example 1 :
// let cities = ["delhi", "kolkata", "luckhnow", "mumbai", "pune"];
// for (let city of cities){
//     console.log(city);
// }
//Output will be : delhi
// arrays.js:92 kolkata
// arrays.js:92 luckhnow
// arrays.js:92 mumbai
// arrays.js:92 pune


// Example 2 : 
// let cities = ["delhi", "kolkata", "luckhnow", "mumbai", "pune"];
// for (let city of cities){
//     console.log(city.toUpperCase());
// }

// Output will be : 
// DELHI
// KOLKATA
// LUCKHNOW
// MUMBAI
// PUNE

// Arrays Methods
// Push() : add to end 
// pop(): delete from end & return
// to string() : converts array to string

// Example 1 Push() : add to end :
// let foodItems = ["potato", "apple", "litchi", "tomato"];
// foodItems.push("chips");
// console.log(foodItems);
// Output will be : (5) ['potato', 'apple', 'litchi', 'tomato', 'chips']


// Example 2 pop(): delete from end & return : 
// foodItems.pop()
// console.log(foodItems);
//(4) ['potato', 'apple', 'litchi', 'tomato']
// Or 
// let fastfood = ["burger", "pasta", "coke", "french fries"];
// fastfood.pop();
// console.log(fastfood);
//(3) ['burger', 'pasta', 'coke']

// Or log the deleted items :
// let deletedItems = fastfood.pop();
// console.log(deletedItems);
// Output will be : french fries


// Example 3 to string() : converts array to string : 
// let itemstoString = fastfood.toString();
// console.log(itemstoString);
// Output will be : burger,pasta,coke 




// Array Methods : 

// Concat Method
// let marvel_heroes = ["thor", "spiderman", "ironman"];
// let dc_heroes = ["superman", "batman"];
// let inian_Heroes = ["Shaktiman", "Balveer"];
// let allheroes = marvel_heroes.concat(dc_heroes);
// let heroes = marvel_heroes.concat(dc_heroes,inian_Heroes);

// Output will be : 
// console.log(heroes);
// Output will be : (5) ['thor', 'spiderman', 'ironman', 'superman', 'batman']
// console.log(allheroes);
// Output will be : (7) ['thor', 'spiderman', 'ironman', 'superman', 'batman', 'Shaktiman', 'Balveer']



// Unshift Method : its add arrays value on start
// marvel_heroes.unshift("antman");

// & similarly shift : to delete the value 
// let marvel_heroes = ["thor", "spiderman", "ironman"];
// let value = marvel_heroes.shift("thor");
// console.log("deleted" ,value,marvel_heroes);
// Output will be : (2) ['spiderman', 'ironman']



// slice method : 

// let dc_heroes = ["superman", "batman"];
// let slicevalue = dc_heroes.slice();
// console.log(slicevalue);

// slice method with excluded terms :
// console.log(slicevalue.slice(0,1));
// Output will be from excluding 1st term : ['superman'] 0th term



// Splice() method : change original array (go to index, remove, replace)
// let arr = ["fuchka", "egg roll", "chaomin", "ice cream", "coke", "cake" ];
// let arrsplice = arr;
// console.log("Full Term = ",arrsplice,"final term will be : ", arr.splice(2,2,"mouthfreshner", "silver pearls"));
// // Output will be :  final term will be :  (2) ['chaomin', 'ice cream']
// console.log(arr); // Output will be : (6) ['fuchka', 'egg roll', 'mouthfreshner', 'silver pearls', 'coke', 'cake']