Is there a record log for the werewolf in the book "Articulate Coding: The Lycanthrope's

Question

Is there a record log for the werewolf in the book "Articulate Coding: The Lycanthrope's

I've been tackling the challenges of Eloquent JavaScript at the Lycanthrope's Log, but I'm struggling to grasp a particular code snippet. Despite my efforts in checking values and testing with console.log, this piece of code still eludes me:

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},
  // ...
]

function hasEvent(event, entry) {
  return entry.events.indexOf(event) != -1; // verifying if event occurred or not 
}

function tableFor(event, journal) {
  var table = [0, 0, 0, 0];
  for (var i = 0; i < journal.length; i++) {
   var entry = journal[i], index = 0;

   if (hasEvent(event, entry)) index += 1; // adding +1 to index if pizza happened
    //object of arrays --> console.log(entry); 
   if (entry.squirrel) index += 2; // increasing index by 2 if squirrel is true
   table[index] += 1; //<<-- This part is puzzling me 
   // console.log(index);
  }
 return table;
}

console.log(tableFor("pizza", JOURNAL));
// How are these values being calculated and added on indexes? Can someone help clarify this program for me?

If anyone can shed some light on how the values are processed and inserted into the array indexes, I would greatly appreciate it.

javascript

Answer 1

Answer №1

When we dive into each item from the JOURNAL collection, the table indexes signify specific scenarios:

table[0] increments by +1 if the event is absent in item.events and squirrel: false
table[1] increments by +1 if the event is present in item.events and squirrel: false
table[2] increments by +1 if the event is absent in item.events and squirrel: true
table[3] increments by +1 if the event is present in item.events and squirrel: true

Essentially, this table tracks different combinations of the squirrel and pizza variables. Ultimately, the table is utilized in the phi function to compute the correlation between these variables.

It's worth noting that utilizing the suggested formula for phi could simplify the process by transforming the table into a 2x2 matrix with entries like

table[0][0], table[0][1], table[1][0], and table[1][1]

, where rows denote the squirrel's state and columns indicate the presence of pizza in item.events.

Answer 2

When we dive into each item from the JOURNAL collection, the table indexes signify specific scenarios:

table[0] increments by +1 if the event is absent in item.events and squirrel: false
table[1] increments by +1 if the event is present in item.events and squirrel: false
table[2] increments by +1 if the event is absent in item.events and squirrel: true
table[3] increments by +1 if the event is present in item.events and squirrel: true

Essentially, this table tracks different combinations of the squirrel and pizza variables. Ultimately, the table is utilized in the phi function to compute the correlation between these variables.

It's worth noting that utilizing the suggested formula for phi could simplify the process by transforming the table into a 2x2 matrix with entries like

table[0][0], table[0][1], table[1][0], and table[1][1]

, where rows denote the squirrel's state and columns indicate the presence of pizza in item.events.

Answer 3

Answer №2

According to the explanation in Eloquent Javascript, the journal/log contains around 90 entries JOURNAL.length

function tableFor(event, journal) {
  var table = [0, 0, 0, 0];

//A table with 4 figures is declared here for future incrementation,

  for (var i = 0; i < journal.length; i++) {
   var entry = journal[i], index = 0;

//A loop for journal.length initialization

Keep in mind that JOURNAL.length = 90, so this loop will iterate 90 times.

The first iteration of this loop sets i = 0 , and

journal[i] = {"events":["carrot","exercise","weekend"],"squirrel":false}

, index = 0 while checking for "pizza"

if (hasEvent(event, entry)) index += 1; 

//When this if statement in the loop evaluates, if(hasEvent(event, entry)) returns False, hence index = 0

if (entry.squirrel) index += 2;

//Moving forward in the loop, the entry.squirrel value being False results in no increment,
//So, the index remains at 0.

//NOTE: The increment pertains to the 'index' variable, not the 'table index'.

//At this point before the following code line, index still equals 0 (for the initial journal[i] where i=0)
//Since this is the first cycle (i=0), table remains [0,0,0,0]

 table[index] += 1; 

//Considering table[index] as table[0] which by now equals 0,
//Performing table[index] = table[index] + 1 equates to table[index]= 0+1.
//Updating table[index] += 0 where index = 0 leads to adding 1 to the first item in the table array.

//With this step, the table status shifts to [1, 0, 0, 0] but there are 89 more cycles to go.
  }

//Upon completion of all iterations, table becomes [76, 9, 4, 1]
 return table;
}

In the code you provided, JOURNAL holds only 3 entries, therefore

console.log(tableFor("pizza", JOURNAL))

Outputs: table = [3, 0, 0, 0];

Answer 4

According to the explanation in Eloquent Javascript, the journal/log contains around 90 entries JOURNAL.length

function tableFor(event, journal) {
  var table = [0, 0, 0, 0];

//A table with 4 figures is declared here for future incrementation,

  for (var i = 0; i < journal.length; i++) {
   var entry = journal[i], index = 0;

//A loop for journal.length initialization

Keep in mind that JOURNAL.length = 90, so this loop will iterate 90 times.

The first iteration of this loop sets i = 0 , and

journal[i] = {"events":["carrot","exercise","weekend"],"squirrel":false}

, index = 0 while checking for "pizza"

if (hasEvent(event, entry)) index += 1; 

//When this if statement in the loop evaluates, if(hasEvent(event, entry)) returns False, hence index = 0

if (entry.squirrel) index += 2;

//Moving forward in the loop, the entry.squirrel value being False results in no increment,
//So, the index remains at 0.

//NOTE: The increment pertains to the 'index' variable, not the 'table index'.

//At this point before the following code line, index still equals 0 (for the initial journal[i] where i=0)
//Since this is the first cycle (i=0), table remains [0,0,0,0]

 table[index] += 1; 

//Considering table[index] as table[0] which by now equals 0,
//Performing table[index] = table[index] + 1 equates to table[index]= 0+1.
//Updating table[index] += 0 where index = 0 leads to adding 1 to the first item in the table array.

//With this step, the table status shifts to [1, 0, 0, 0] but there are 89 more cycles to go.
  }

//Upon completion of all iterations, table becomes [76, 9, 4, 1]
 return table;
}

In the code you provided, JOURNAL holds only 3 entries, therefore

console.log(tableFor("pizza", JOURNAL))

Outputs: table = [3, 0, 0, 0];

Is there a record log for the werewolf in the book "Articulate Coding: The Lycanthrope's

Answer №1

Answer №2

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