Is there a simpler method for tallying identical items occurring consecutively in an array?

Question

Is there a simpler method for tallying identical items occurring consecutively in an array?

This is my unique code snippet

function countTriplets(arr){
    let sequence = (arr.join(''));
    let pointer = -1;
    let tripletCount = 0;

    const findTriplet = (char, start) => {
        return sequence.indexOf(char, start + 1);
    }

    const updateCount = () => {
        tripletCount++;
        pointer += 3;
    }
    
    while((pointer = findTriplet('hhh', pointer)) !== -1 ){
        updateCount();
    }

    while((pointer = findTriplet('ttt', pointer)) !== -1 ){
        updateCount();
    }

    console.log(tripletCount);
}

countTriplets(["h", "h", "h", "t", "h", "h", "t", "t", "t", "h", "t", "h", "h", "h", "h"]);

In this implementation, I aim to determine the number of times 't' or 'h' occur consecutively three times in a row.

I am exploring if there exists an efficient way to accomplish this without converting the array into a string or merging the two while loops.

javascript arrays counting

Answer 1

Answer №1

You can loop through each item in the array.

While iterating, you should keep track of:

the total count of repeated groups encountered (total)
the value of the last element seen in the array (previousElement)
the current count of elements that have repeated so far (currentCount)

Here is a practical example illustrating the concept mentioned above, along with explanatory comments:

function countRepeats (numOfRepeated, array) {
  let total = 0;
  let currentCount = 0;
  // Initialize previousElement as an empty object to differentiate from other values:
  let previousElement = {};

  for (const element of array) {
    if (element === previousElement) {
      // Increment the count:
      currentCount += 1;

      if (currentCount === numOfRepeated) {
        // Increase the total count:
        total += 1;
        // Reset current count to 1:
        currentCount = 1;
      }
    }
    else {
      // Reset current count to 1:
      currentCount = 1;
    }

    // Update previousElement value:
    previousElement = element;
  }
  
  return total;
}

const total = countRepeats(
  3,
  ["h", "h", "h", "t", "h", "h", "t", "t", "t", "h", "t", "h", "h", "h", "h"],
//  1    2    3    1    1    2    1    2    3    1    1    1    2    3    1
//            1                             2                        3
);

console.log(total); // 3

Answer 2

You can loop through each item in the array.

While iterating, you should keep track of:

the total count of repeated groups encountered (total)
the value of the last element seen in the array (previousElement)
the current count of elements that have repeated so far (currentCount)

Here is a practical example illustrating the concept mentioned above, along with explanatory comments:

function countRepeats (numOfRepeated, array) {
  let total = 0;
  let currentCount = 0;
  // Initialize previousElement as an empty object to differentiate from other values:
  let previousElement = {};

  for (const element of array) {
    if (element === previousElement) {
      // Increment the count:
      currentCount += 1;

      if (currentCount === numOfRepeated) {
        // Increase the total count:
        total += 1;
        // Reset current count to 1:
        currentCount = 1;
      }
    }
    else {
      // Reset current count to 1:
      currentCount = 1;
    }

    // Update previousElement value:
    previousElement = element;
  }
  
  return total;
}

const total = countRepeats(
  3,
  ["h", "h", "h", "t", "h", "h", "t", "t", "t", "h", "t", "h", "h", "h", "h"],
//  1    2    3    1    1    2    1    2    3    1    1    1    2    3    1
//            1                             2                        3
);

console.log(total); // 3

Is there a simpler method for tallying identical items occurring consecutively in an array?

Answer №1

Similar questions

What is the best way to display output within an array using PHP?

What is the best way to implement multiple store filters in VueJS?

Performing calculations involving both select and checkbox input values, as well as handling negative numbers

What is the process for adding custom keys to a sequential array or collection of arrays with Laravel or PHP?

By setting `queue: false` when calling jQuery's `show()` method, you can

What could be the reason why the navbar ul li a instance is not appearing in Bootstrap 4 modal when using an

How do I prevent my image slider from scrolling to the top of the page when I click next or prev?

Updating NPM packages versions is currently restricted

Using jQuery to implement translation on scroll

Unable to Retrieve Stripe Connect Account Balance

Tips for automatically filling in fields when a button is clicked in a React application

A guide on acquiring interactive documents from Google Drive

Is the referencing of array elements specific to the implementation of the compiler?

Why would one pass in the value of undefined?

Can you provide an explanation of what the 'attribution' key does in the tomTomMap.addSource() function?

Combining synchronous and asynchronous code in JavaScript with Node.js and MongoDB

The Vue instance methods provide a way to access and manipulate formatted properties

Working with PHP Multidimensional Associative Arrays: How to Retrieve a List of Keys?

Configuring local fonts in Puppeteer using npm

Tips for activating text selection in PDF.js