What is the best way to combine and calculate elements in an array that is nested within an array using a specific condition or rule?

Question

What is the best way to combine and calculate elements in an array that is nested within an array using a specific condition or rule?

I have a JavaScript array of arrays with different data types that looks like this:

let bigArray = [["A", "B", 221.67],["C", "B", 221.65],["B", "D", 183.33],["B", "A", 4900],["E", "B", 150],["A", "B", 150]]

Now I need to add the third element (a number) if the first and second elements match with the next array's first and second elements, and also subtract the third elements if a reverse match is found.

The expected output will be:

let ans = [["B", "A", 4528.33],["C", "B", 221.65],["B", "D", 183.33],["E", "B", 150]]

The subarray ["B","A", 4528.33] is achieved by performing subtraction operation as 4900-221.67-150

In bigArray, there are arrays with repeated pairs of elements such as "A" and "B". For all matching subarrays, perform addition and for reverse matches, perform subtraction. Example: 4900-221.67-150

I have tried various methods but couldn't achieve the desired output consistently. Any assistance would be greatly appreciated. Thank you!

javascript arrays data-structures merge reduce

Answer 1

Answer №1

To maintain a standard key, grouping with sorted keys can be done to ensure the same order of part keys. Then, values can be added or subtracted accordingly.

If any value is negative, changing the keys and converting it into a positive value is necessary.

let data = [["A", "B", 221.67], ["C", "B", 221.65], ["B", "D", 183.33], ["B", "A", 4900], ["E", "B", 150], ["A", "B", 150]],
    result = Object.values(data.reduce((r, [a, b, v]) => {
        const key = [a, b].sort().join('|');
        if (r[key]) {
            r[key][2] += a === r[key][0] ? v : -v;
            if (r[key][2] < 0) r[key] = [r[key][1], r[key][0], -r[key][2]];
        } else {
            r[key] = [a, b, v];
        }
        return r;
    }, {}));

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

To maintain a standard key, grouping with sorted keys can be done to ensure the same order of part keys. Then, values can be added or subtracted accordingly.

If any value is negative, changing the keys and converting it into a positive value is necessary.

let data = [["A", "B", 221.67], ["C", "B", 221.65], ["B", "D", 183.33], ["B", "A", 4900], ["E", "B", 150], ["A", "B", 150]],
    result = Object.values(data.reduce((r, [a, b, v]) => {
        const key = [a, b].sort().join('|');
        if (r[key]) {
            r[key][2] += a === r[key][0] ? v : -v;
            if (r[key][2] < 0) r[key] = [r[key][1], r[key][0], -r[key][2]];
        } else {
            r[key] = [a, b, v];
        }
        return r;
    }, {}));

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

What is the best way to combine and calculate elements in an array that is nested within an array using a specific condition or rule?

Answer №1

Similar questions

Techniques for removing invalid characters from a JSON $http.get() request

In order to delete a post within a Node.js application, you must double-click the delete button

Ways to simultaneously apply fade in and fade out effects using CSS

what is the best way to display a chosen value in a dropdown menu using jQuery?

Unexpected behavior when using ng-if within ng-repeat

Unpack and retrieve multiple values

DayClick function in FullCalendar plugin is malfunctioning

Experiencing issues with recognizing HTML DOM functions during Jest testing

Can you please explain the process of retrieving the value of an item from a drop-down menu using JavaScript?

Creating user input fields with rich text formatting capabilities in Ruby on Rails

Exploring the Process of Setting Up a Temporary Endpoint in Express

Challenges with 'this' reference in a requireif causing Vuelidate complications

Unable to capture HTML form input in $_POST[]

Combining Angular JS with JSP and Servelet

Exploring ways to utilize fetch results within a return statement in React

Assigning and retrieving values from PHP arrays to access variable values

Struggling with an Ember project: dynamically populating a form field upon selection

Learning to extract URL parameters in ReactJS is a valuable skill

Maximizing the potential of NPM modules by harnessing the power of the package.json file

Default value for nonexisting indices in a PHP array