kironroy

// All numbers are represented as floating point numbers in JS
// Numbers stored in binary format 64 bit
// In binary form fractions are hard to represent

console.log(23 === 23.0);
console.log(0.1 + 0.2 === 0.3); // =(

// conversion
console.log(Number('23'));
console.log(+'23'); // type coercion

kironroy

'use strict';

// Data
// forEach

const info1 = {
  owner: 'Sita Troy',
  movements: [200, 450, -400, 3000, -650, -130, 70, 1300],
  interestRate: 1.2, // %
  pin: 1111,

kironroy

// what do i want from this method?
// mutate an array, create a new array
// array includes
// array transform

// methods that MUTATE original array
// + add to original:  .push, ,.unshift (start)
// - remove from original: .pop (end), .shift, .splice
//   others: .reverse, .sort, .fill

kironroy

// try 100 random dice rolls

// create array of 100 numbers (1 to 100)
const diceRollsArr = Array.from({length: 100}, (_, i) => i + 1);
console.log(Array.isArray(diceRollsArr));

// sort array (random)
const rdmDiceRollsArr = diceRollsArr.sort((a, b) => 0.5 - Math.random());

console.log(diceRollsArr);

kironroy

const movements = [200, 450, -400, 3000, -650, -130, 70, 1300];

// descending 
movements.sort((a, b) => {
  if (a > b) return 1;
  if (b > a) return -1;
});

console.log(movements);

kironroy

// Data

const account1 = {
  owner: 'Bobby Khan',
  movements: [2030, 450, -400, 3000, -650, -130, 70, 1300],
  interestRate: 1.2, // %
  pin: 11411,
};

const account2 = {

kironroy

const movements3 = [200, 450, -400, 3000, -650, -130, 70, 1300];
console.log(movements3);

// equality
console.log(movements3.includes(-130));

// some condition
const anyDeposits = movements3.some(mov => mov > 1500);
console.log(anyDeposits);

kironroy

// https://stackoverflow.com/questions/6866196/javascript-multiply-and-sum-two-arrays

// (4*2+3*3+4*3+5*1).
const arr1 = [2, 3, 4, 5];
const arr2 = [4, 3, 3, 1];
console.log(arr1.reduce((r, a, i) => r + a * arr2[i], 0));
// 34

// https://www.w3schools.com/ai/ai_matrices.asp

kironroy

const movements2 = [200, 450, -400, 3000, -650, -130, 70, 1300];

const firstWithdrawal = movements2.find(mov => mov < 0);

console.log(movements2);
console.log(firstWithdrawal);

// array of objects is a common data structure
console.log(accounts);

kironroy

const agesOneArr = [5, 2, 4, 1, 15, 8, 3];
const agesTwoArr = [16, 6, 10, 5, 6, 1, 4];

const calcAverageHumanAge = function (ages) {
  const dogToHumanYrs = ages.map((age, i) =>
    age <= 2 ? 2 * age : 16 + age * 4
  );
  const eighteenOrOlder = dogToHumanYrs.filter(age => age > 18);
  console.log(eighteenOrOlder);