Module 4: Practical Examples of Google Sheets Custom Functions

Key Takeaways:

– Understand the real-world applications of custom functions in Google Sheets

– Learn how to create custom functions for data validation, unit conversion, and other practical uses

– Discover how custom functions can optimize your workflow

Introduction: Real-World Applications of Custom Functions

Now that you have a solid understanding of custom functions and their capabilities, it’s time to put the theory into practice. In this module, we’ll explore some practical examples of custom functions that can streamline your work in Google Sheets. Let’s dive in and create custom functions that solve common spreadsheet problems!

4.1 Custom Function for Data Validation

Data validation is crucial to maintain the integrity and accuracy of your spreadsheet data. While Google Sheets offers a built-in data validation feature, it may not cover complex scenarios or specific requirements. In such cases, a custom function can fill this gap.

Example: Validation of email addresses

Using Google Sheets’ built-in REGEXMATCH function, you can create a custom function to validate email addresses entered into a cell.

function validateEmail(address) {
  var emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
  return emailRegex.test(address) ? "Valid" : "Invalid";

To use this function in your sheet, enter `=validateEmail(Cell)` replacing “Cell” with the cell containing the email address.

4.2 Custom Function for Unit Conversions

Google Sheets lacks a comprehensive set of unit conversion functions. Creating custom functions can simplify complex conversions and improve the readability of your sheet.

Example: Converting kilometers to miles

function kmToMiles(kilometers) {
  var miles = kilometers * 0.621371;
  return miles;

To use this function in your sheet, enter `=kmToMiles(Cell)` replacing “Cell” with the cell containing the kilometers value.

4.3 Custom Function for Currency Conversion

Currency conversion is a common use case for custom functions. While the built-in GOOGLEFINANCE function can provide live currency exchange rates, it may not fulfill all your requirements.

Example: Customized currency conversion using Google Finance API

function currencyConversion(amount, fromCurrency, toCurrency) {
  var apiUrl = ''+fromCurrency+'-'+toCurrency+'?sa=X&ved=0ahUKEwjW29bBwJfYAhUD2lMKHaDCAo4Q3yhGMAp6BAhSEAE';
  var response = UrlFetchApp.fetch(apiUrl);
  var rate = parseFloat(response.split("(")[1].split(")")[0]);
  var convertedAmount = amount * rate;
  return convertedAmount;

To use this function in your sheet, enter `=currencyConversion(amount, “fromCurrency”, “toCurrency”)` replacing “amount” with the value, and “fromCurrency”, “toCurrency” with the desired currency codes (e.g., USD, EUR).

4.4 Custom Function for Parsing and Structuring Complex Data

Custom functions can be highly valuable when working with large datasets, helping to parse, filter, and restructure data for analysis.

Example: Extract URLs from a block of text

function extractUrls(text) {
  var urlRegex = /https?:\/\/(?:[a-zA-Z]|[0-9]|[$-_@.&+]|[!*\\(\\),]|(?:%[0-9a-fA-F][0-9a-fA-F]))+/g;
  var urls = text.match(urlRegex);
  return urls.join("\n");

To use this function in your sheet, enter `=extractUrls(Cell)` replacing “Cell” with the cell containing the text.

4.5 Custom Function for Automating Workflow

Custom functions can help automate repetitive tasks, saving time and effort.

Example: Automatically send email reminders based on due dates

function sendEmailReminder() {
  // Set up your sheet and range to check for due dates
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Tasks");
  var dataRange = sheet.getRange(2, 1, sheet.getLastRow()-1, 6);
  var data = dataRange.getValues();

  // Set the condition for when an email should be sent
  var currentDate = new Date();
  for (var i = 0; i < data.length; i++) {
    var task = data[i];
    var dueDate = new Date(task[4]);
    var daysDiff = (dueDate - currentDate) / (1000 * 60 * 60 * 24);

    if (daysDiff <= 1) {
      // Customize email content
      var subject = "Task Reminder: " + task[1];
      var message = "This is your reminder for the task: " + task[1] + " which is due on " + dueDate;

      // Send email to the assigned person
      MailApp.sendEmail(task[2], subject, message);

To use this function, you’ll need to set up a time-based trigger in the Google Apps Script editor. This will allow the function to run automatically at a specified time, sending email reminders when a due date is approaching.


Q: Can I create custom functions that interact with external APIs?

A: Yes. You can use Google Sheets custom functions to fetch data from external APIs, parse the response, and display it within your sheet. This will allow you to integrate up-to-date information from various sources directly into your spreadsheet.

Q: How do I share my custom functions with my team members?

A: There are two primary methods. First, share access to the Google Sheet containing the custom functions with your team. Second, export your custom functions as an add-on, allowing others to easily import and use them within their spreadsheets.

Module Summary and Key Takeaways:

In this module, we applied the knowledge gained from the previous lessons and built practical custom functions for data validation, unit conversions, currency conversions, parsing complex data, and automation. These examples demonstrate the immense potential of custom functions to solve real-world problems and ease your workflow. As you continue to master custom functions, you’ll uncover even more possibilities and applications for Google Sheets.

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