eloquentJS_04-Data StructuresObjects and Arrays

let journal = [
  {events: ["work", "touched tree", "pizza",
            "running", "television"],
   squirrel: false},
  {events: ["work", "ice cream", "cauliflower",
            "lasagna", "touched tree", "brushed teeth"],
   squirrel: false},
  {events: ["weekend", "cycling", "break", "peanuts",
            "beer"],
   squirrel: true},
  /* and so on... */
];

function addEntry(events, squirrel) {
  journal.push({events, squirrel});
}

var JOURNAL = [
  {"events":["carrot","exercise","weekend"],"squirrel":false},
  {"events":["bread","pudding","brushed teeth","weekend","touched tree"],"squirrel":false},
  {"events":["carrot","nachos","brushed teeth","cycling","weekend"],"squirrel":false},
  {"events":["brussel sprouts","ice cream","brushed teeth","computer","weekend"],"squirrel":false},
  {"events":["potatoes","candy","brushed teeth","exercise","weekend","dentist"],"squirrel":false},
  {"events":["brussel sprouts","pudding","brushed teeth","running","weekend"],"squirrel":false},
  {"events":["pizza","brushed teeth","computer","work","touched tree"],"squirrel":false},
  {"events":["bread","beer","brushed teeth","cycling","work"],"squirrel":false},
  {"events":["cauliflower","brushed teeth","work"],"squirrel":false},
  {"events":["pizza","brushed teeth","cycling","work"],"squirrel":false},
  {"events":["lasagna","nachos","brushed teeth","work"],"squirrel":false},
  {"events":["brushed teeth","weekend","touched tree"],"squirrel":false},
  {"events":["lettuce","brushed teeth","television","weekend"],"squirrel":false},
  {"events":["spaghetti","brushed teeth","work"],"squirrel":false},
  {"events":["brushed teeth","computer","work"],"squirrel":false},
  {"events":["lettuce","nachos","brushed teeth","work"],"squirrel":false},
  {"events":["carrot","brushed teeth","running","work"],"squirrel":false},
  {"events":["brushed teeth","work"],"squirrel":false},
  {"events":["cauliflower","reading","weekend"],"squirrel":false},
  {"events":["bread","brushed teeth","weekend"],"squirrel":false},
  {"events":["lasagna","brushed teeth","exercise","work"],"squirrel":false},
  {"events":["spaghetti","brushed teeth","reading","work"],"squirrel":false},
  {"events":["carrot","ice cream","brushed teeth","television","work"],"squirrel":false},
  {"events":["spaghetti","nachos","work"],"squirrel":false},
  {"events":["cauliflower","ice cream","brushed teeth","cycling","work"],"squirrel":false},
  {"events":["spaghetti","peanuts","computer","weekend"],"squirrel":true},
  {"events":["potatoes","ice cream","brushed teeth","computer","weekend"],"squirrel":false},
  {"events":["potatoes","ice cream","brushed teeth","work"],"squirrel":false},
  {"events":["peanuts","brushed teeth","running","work"],"squirrel":false},
  {"events":["potatoes","exercise","work"],"squirrel":false},
  {"events":["pizza","ice cream","computer","work"],"squirrel":false},
  {"events":["lasagna","ice cream","work"],"squirrel":false},
  {"events":["cauliflower","candy","reading","weekend"],"squirrel":false},
  {"events":["lasagna","nachos","brushed teeth","running","weekend"],"squirrel":false},
  {"events":["potatoes","brushed teeth","work"],"squirrel":false},
  {"events":["carrot","work"],"squirrel":false},
  {"events":["pizza","beer","work","dentist"],"squirrel":false},
  {"events":["lasagna","pudding","cycling","work"],"squirrel":false},
  {"events":["spaghetti","brushed teeth","reading","work"],"squirrel":false},
  {"events":["spaghetti","pudding","television","weekend"],"squirrel":false},
  {"events":["bread","brushed teeth","exercise","weekend"],"squirrel":false},
  {"events":["lasagna","peanuts","work"],"squirrel":true},
  {"events":["pizza","work"],"squirrel":false},
  {"events":["potatoes","exercise","work"],"squirrel":false},
  {"events":["brushed teeth","exercise","work"],"squirrel":false},
  {"events":["spaghetti","brushed teeth","television","work"],"squirrel":false},
  {"events":["pizza","cycling","weekend"],"squirrel":false},
  {"events":["carrot","brushed teeth","weekend"],"squirrel":false},
  {"events":["carrot","beer","brushed teeth","work"],"squirrel":false},
  {"events":["pizza","peanuts","candy","work"],"squirrel":true},
  {"events":["carrot","peanuts","brushed teeth","reading","work"],"squirrel":false},
  {"events":["potatoes","peanuts","brushed teeth","work"],"squirrel":false},
  {"events":["carrot","nachos","brushed teeth","exercise","work"],"squirrel":false},
  {"events":["pizza","peanuts","brushed teeth","television","weekend"],"squirrel":false},
  {"events":["lasagna","brushed teeth","cycling","weekend"],"squirrel":false},
  {"events":["cauliflower","peanuts","brushed teeth","computer","work","touched tree"],"squirrel":false},
  {"events":["lettuce","brushed teeth","television","work"],"squirrel":false},
  {"events":["potatoes","brushed teeth","computer","work"],"squirrel":false},
  {"events":["bread","candy","work"],"squirrel":false},
  {"events":["potatoes","nachos","work"],"squirrel":false},
  {"events":["carrot","pudding","brushed teeth","weekend"],"squirrel":false},
  {"events":["carrot","brushed teeth","exercise","weekend","touched tree"],"squirrel":false},
  {"events":["brussel sprouts","running","work"],"squirrel":false},
  {"events":["brushed teeth","work"],"squirrel":false},
  {"events":["lettuce","brushed teeth","running","work"],"squirrel":false},
  {"events":["candy","brushed teeth","work"],"squirrel":false},
  {"events":["brussel sprouts","brushed teeth","computer","work"],"squirrel":false},
  {"events":["bread","brushed teeth","weekend"],"squirrel":false},
  {"events":["cauliflower","brushed teeth","weekend"],"squirrel":false},
  {"events":["spaghetti","candy","television","work","touched tree"],"squirrel":false},
  {"events":["carrot","pudding","brushed teeth","work"],"squirrel":false},
  {"events":["lettuce","brushed teeth","work"],"squirrel":false},
  {"events":["carrot","ice cream","brushed teeth","cycling","work"],"squirrel":false},
  {"events":["pizza","brushed teeth","work"],"squirrel":false},
  {"events":["spaghetti","peanuts","exercise","weekend"],"squirrel":true},
  {"events":["bread","beer","computer","weekend","touched tree"],"squirrel":false},
  {"events":["brushed teeth","running","work"],"squirrel":false},
  {"events":["lettuce","peanuts","brushed teeth","work","touched tree"],"squirrel":false},
  {"events":["lasagna","brushed teeth","television","work"],"squirrel":false},
  {"events":["cauliflower","brushed teeth","running","work"],"squirrel":false},
  {"events":["carrot","brushed teeth","running","work"],"squirrel":false},
  {"events":["carrot","reading","weekend"],"squirrel":false},
  {"events":["carrot","peanuts","reading","weekend"],"squirrel":true},
  {"events":["potatoes","brushed teeth","running","work"],"squirrel":false},
  {"events":["lasagna","ice cream","work","touched tree"],"squirrel":false},
  {"events":["cauliflower","peanuts","brushed teeth","cycling","work"],"squirrel":false},
  {"events":["pizza","brushed teeth","running","work"],"squirrel":false},
  {"events":["lettuce","brushed teeth","work"],"squirrel":false},
  {"events":["bread","brushed teeth","television","weekend"],"squirrel":false},
  {"events":["cauliflower","peanuts","brushed teeth","weekend"],"squirrel":false}
];


 <!-- 1. 滿足pizza 的 在JOURNAL[1]   +=1 -->
 <!-- 2. 滿足 (entry.squirrel) == true 的 在JOURNAL[2] += 1 -->
 <!-- 3. 同時滿足以上兩個條件的 在JOURNAL[3] +=1 -->
function tableFor(event, journal) {
  let table = [0, 0, 0, 0];
  for (let i = 0; i < journal.length; i++) {
    let entry = journal[i], index = 0;
    if (entry.events.includes(event)) index += 1;
    if (entry.squirrel) index += 2;
    table[index] += 1;
    console.log(table);
  }
  
  return table;
}

console.log(tableFor("pizza", JOURNAL));
// → [76, 9, 4, 1]

for (let entry of journal) {
  console.log(`${entry.events.length} events.`);
}

function journalEvents(journal) {
  let events = [];
  for (let entry of journal) {
    for (let event of entry.events) {
      if (!events.includes(event)) {
        events.push(event);
      }
    }
  }
  return events;
}

console.log(journalEvents(journal));
console.log(journalEvents(JOURNAL));

for (let event of journalEvents(JOURNAL)) {
  console.log(event + ":", phi(tableFor(event, JOURNAL)));
}

for (let event of journalEvents(JOURNAL)) {
  let correlation = phi(tableFor(event, JOURNAL));
  if (correlation > 0.1 || correlation < -0.1) {
    console.log(event + ":", correlation);
  }
}

for (let entry of JOURNAL) {
  if (entry.events.includes("peanuts") &&
     !entry.events.includes("brushed teeth")) {
    entry.events.push("peanut teeth");
  }
}
console.log(phi(tableFor("peanut teeth", JOURNAL)));
// → 1

let todoList = [];
function remember(task) {
  todoList.push(task);
}
function getTask() {
  return todoList.shift();
}
function rememberUrgently(task) {
  todoList.unshift(task);
}

console.log([1, 2, 3, 2, 1].indexOf(2));
// → 1
console.log([1, 2, 3, 2, 1].lastIndexOf(2));
// → 3

console.log([0, 1, 2, 3, 4].slice(2, 4));
// → [2, 3]
console.log([0, 1, 2, 3, 4].slice(2));
// → [2, 3, 4]

function remove(array, index) {
  return array.slice(0, index)
    .concat(array.slice(index + 1));
}
console.log(remove(["a", "b", "c", "d", "e"], 2));
// → ["a", "b", "d", "e"]

console.log("coconuts".slice(4, 7));
// → nut
console.log("coconut".indexOf("u"));
// → 5

console.log("  okay \n ".trim());
// → okay

console.log(String(6).padStart(3, "0"));
// → 006

let sentence = "Secretarybirds specialize in stomping";
let words = sentence.split(" ");
console.log(words);
// → ["Secretarybirds", "specialize", "in", "stomping"]
console.log(words.join(". "));
// → Secretarybirds. specialize. in. stomping

function max(...numbers) {
  let result = -Infinity;
  for (let number of numbers) {
    if (number > result) result = number;
  }
  return result;
}
console.log(max(4, 1, 9, -2));
// → 9

let numbers = [5, 1, 7];
console.log(max(...numbers));
// → 7

let words = ["never", "fully"];
console.log(["will", ...words, "understand"]);
// → ["will", "never", "fully", "understand"]

function randomPointOnCircle(radius) {
  let angle = Math.random() * 2 * Math.PI;
  return {x: radius * Math.cos(angle),
          y: radius * Math.sin(angle)};
}
console.log(randomPointOnCircle(2));
// → {x: 0.3667, y: 1.966}

console.log(Math.random());
// → 0.36993729369714856
console.log(Math.random());
// → 0.727367032552138
console.log(Math.random());
// → 0.40180766698904335

let {name} = {name: "Faraji", age: 23};
console.log(name);
// → Faraji

let string = JSON.stringify({squirrel: false,
                             events: ["weekend"]});
console.log(string);
// → {"squirrel":false,"events":["weekend"]}
console.log(JSON.parse(string).events);
// → ["weekend"]

// Your code here.

console.log(range(1, 10));
// → [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
console.log(range(5, 2, -1));
// → [5, 4, 3, 2]
console.log(sum(range(1, 10)));
// → 55

// Your code here.

console.log(reverseArray(["A", "B", "C"]));
// → ["C", "B", "A"];
let arrayValue = [1, 2, 3, 4, 5];
reverseArrayInPlace(arrayValue);
console.log(arrayValue);
// → [5, 4, 3, 2, 1]

function arrayToList(array) {
  var list = null;
  for (var i = array.length - 1; i >= 0; i--)
    list = {value: array[i], rest: list};
  return list;
}

function listToArray(list) {
  var array = [];
  for (var node = list; node; node = node.rest) {
    array.push(node.value);
  }
  return array;
}

function prepend(value, list) {
  return {value: value, rest: list};
}

function nth(list, n) {
  if (!list) {
    return undefined;
  } else if (n === 0) {
    return list.value;
  } else {
    return nth(list.rest, n - 1);
  }
}

console.log(arrayToList([10, 20, 30]));
// → {value: 10, rest: {value: 20, rest: null}}

//console.log(listToArray(arrayToList([10, 20, 30])));
console.log(listToArray({value: 10, rest: { value: 20, rest: { value:80, rest: { value: 30, rest: null }} }}));
// → [10, 20, 30]

console.log(prepend(10, prepend(20, null)));
// → {value: 10, rest: {value: 20, rest: null}}
console.log(nth(arrayToList([10, 20, 30]), 1));
// → 20