array list javascript code example

Example 1: list javascript

//Creating a list
var fruits = ["Apple", "Banana", "Cherry"];

//Creating an empty list
var books = [];

//Getting element of list
//Lists are ordered using indexes
//The first element in an list has an index of 0, 
//the second an index of 1,
//the third an index of 2,
//and so on.
console.log(fruits[0]) //This prints the first element 
//in the list fruits, which in this case is "Apple"

//Adding to lists
fruits.push("Orange") //This will add orange to the end of the list "fruits"
fruits[1]="Blueberry" //The second element will be changed to Blueberry

//Removing from lists
fruits.splice(0, 1) //This will remove the first element,
//in this case Apple, from the list
fruits.splice(0, 2) //Will remove first and second element
//Splice goes from index of first argument to index of second argument (excluding second argument)

Example 2: javascript array

//create an array like so:
var colors = ["red","blue","green"];

//you can loop through an array like this:
for (var i = 0; i < colors.length; i++) {
    console.log(colors[i]);
}

Example 3: javascript array read object value in array

var events = [
  {
    userId: 1,
    place: "Wormholes Allow Information to Escape Black Holes",
    name: "Check out this recent discovery about workholes",
    date: "2020-06-26T17:58:57.776Z",
    id: 1
  },
  {
    userId: 1,
    place: "Wormholes Allow Information to Escape Black Holes",
    name: "Check out this recent discovery about workholes",
    date: "2020-06-26T17:58:57.776Z",
    id: 2
  },
  {
    userId: 1,
    place: "Wormholes Allow Information to Escape Black Holes",
    name: "Check out this recent discovery about workholes",
    date: "2020-06-26T17:58:57.776Z",
    id: 3
  }
];
console.log(events[0].place);

Example 4: return array javascript

function func() {
  return [5, "string", {a: 7}];
}

Example 5: javacript array

[element0, element1, ..., elementN]

new Array(element0, element1[, ...[, elementN]])
new Array(arrayLength)

Example 6: list javascript

//Their are no lists in javascript, they are called arays,wich are basically the same thing

var fruits = ['Apple', 'Banana'];

console.log(fruits.length);
// 2
var first = fruits[0];
// Apple

var last = fruits[fruits.length - 1];
// Banana

fruits.forEach(function(item, index, array) {
  console.log(item, index);
});
// Apple 0
// Banana 1

var newLength = fruits.push('Orange');
// ["Apple", "Banana", "Orange"]

var last = fruits.pop(); // deletes orange
// ["Apple", "Banana"];

var first = fruits.shift(); // supprime Apple (au début)
// ["Banana"];

var newLength = fruits.unshift('Strawberry') // adds to the start
// ["Strawberry", "Banana"];

fruits.push('Mango');
// ["Strawberry", "Banana", "Mango"]

var pos = fruits.indexOf('Banana');
// 1

var removedItem = fruits.splice(pos, 1); // deletes on element at the position pos
//removes one element at the position pos
// ["Strawberry", "Mango"]




var vegetables = ['Cabbage', 'Turnip', 'Radish', 'Carrot'];
console.log(vegetables);
// ["Cabbage", "Turnip", "Radish", "Carrot"]

var pos = 1, n = 2;

var removedItems = vegetables.splice(pos, n);
// n defines the number of element to delete starting from pos

console.log(vegetables);
// ["Cabbage", "Carrot"] 
console.log(removedItems);
// ["Turnip", "Radish"] (splice returns list of deleted objects)