Arrays In Javascript

var cars = ["Saab", "Volvo", "BMW"];

var name = cars[0]; //ACCESS ARRAY ELEMENT saab

cars[0] = "Opel";  //CHANGE ARRAY

console.log(cars); //Saab,volvo,BMW //FULL ARRAY ACCESS

cars.toString(); //ARRAY TO STRING

var fruits = ["Banana", "Orange", "Apple", "Mango"];

fruits.pop();              // Removes the last element ("Mango") from fruits and return also

fruits.push("Kiwi");       //  Adds a new element ("Kiwi") to fruits and return new array length

fruits.shift();            // Removes the first element "Banana" from fruits same as pop

fruits.unshift("Lemon");    // Adds a new element "Lemon" to fruits at first pos

delete fruits[0];           // Changes the first element in fruits to undefined

fruits.splice(2, 2, "Lemon", "Kiwi");  //fruits.splice(whereNewElementsAdds,removedElements, "add1element", "add2 ...");

var marr = arr1.concat(arr2,arr3,arr4);  //concate arrays to new arr

fruits.sort();        // Sorts the elements of fruits alphabetically

fruits.reverse();     // Then reverse the order of the elements

var points = [40, 100, 1, 5, 25, 10];

points.sort(function(a, b){return a - b});  //SORT NUMERIC ARRAY ACCENDING

ARRAY ITERATION

var txt="";
var numbers = [45, 4, 9, 16, 25];
numbers.forEach(myFunction);
function myFunction(value, index, array) {
  txt = txt + value + "<br>";
}

ARRAY MAP CREATE NEW ARRAY: to perform function on each element

var numbers1 = [45, 4, 9, 16, 25];
var numbers2 = numbers1.map(myFunction);
function myFunction(value, index, array) {
  return value * 2;
}

ARRAY FILTER: to perform tests

var numbers = [45, 4, 9, 16, 25];
var over18 = numbers.filter(myFunction);
function myFunction(value, index, array) {
  return value > 18;
}

array.indexOf(item, start)

array.lastIndexOf(item, start)