Expressions

Using Add a row into a table is straightforward when Power Automate can see your Excel file and table at design time. Make the file path or table name dynamic, however, and those friendly column inputs disappear. You can solve that with a JSON object, but it introduces a sneaky risk: Excel can silently ignore renamed or deleted columns while the action still reports success. In this post, I’ll show you how to compare the row object you sent with the body returned by Excel, using one simple intersection() expression. If every column is present, the flow continues. If something has changed, the flow deliberately fails and tells you why. ...

What if I told you that most of the variables in your Power Automate flows and Power Apps don’t need to be variables at all? In this post, we’ll explore immutable variables — a technique that can dramatically simplify your solutions, reduce API calls, and make your logic cleaner and easier to maintain. This post builds on concepts demonstrated in the accompanying video, where we go beyond the basics to show you practical applications, performance benefits, and best practices. ...

Can you encrypt and decrypt a string using Power Automate? My son challenged me with this question after covering the Vigenère Cipher in school, and I couldn’t resist building it. In this post, I’ll show you how to implement a full Vigenère Cipher in Power Automate — without a single Apply to Each — and there’s even a live version you can try yourself. What is the Vigenere Cipher? The Vigenere cipher was invented by Blaise de Vigenere in the 16th century. It is a method of encrypting alphabetic text by using a series of interwoven Caesar ciphers, with each letter of the plaintext being shifted based on a keyword. ...

Need to generate sequential, zero-padded unique IDs in Power Automate — for invoices, filenames, or SharePoint list items? In this post, I’ll show you how to increment your unique ID based on the last file or list item and pad it with leading zeros, all without storing the ID in a separate table. List of Invoices Above is an example Microsoft (SharePoint) List with 3 invoices and a sequential InvoiceID. The key requirement here is that previous invoice ID’s, list items or filenames, will not be deleted as we will use the last known ID as a lookup in the next action. Please also ensure that you DO NOT turn on trigger concurrency, as we must assign the ID during each unique flow run when calling get items. ...

If you’ve ever built a Power Automate flow with dozens of conditions or a massive switch statement, you know how quickly things spiral out of control. In this post, I’ll show you a cleaner approach to handling if/else if/else logic — using arrays and the filter action to dramatically simplify your flows. The Problem with Switch and Parallel Actions **The scenario.**You have a mailbox that you are looking to monitor with a cloud flow and if the subject line matches one of ten possible strings, you want to save the body to a list and email a specific line manager. I’ve started to build the switch solution and then realise, one this is getting out of control, my screen isn’t big enough and two, the condition I need is subject line contains. Surely there is a better way? ...

Dealing with escaped characters in Microsoft Forms responses? If you’ve ever tried to loop through multi-select answers in Power Automate and hit the dreaded “result must be a valid array” error, you’re not alone. In this post, I’ll show you the cleanest way to handle escaped JSON — and it’s simpler than you think. The Problem with Escaped Characters When you select the dynamic answer from a question and run it through an apply to each action you get an error: ...

Working with dates in Power Automate can be frustrating — especially when you hit the dreaded “The datetime string must match ISO 8601 format” error. In this post, I’ll walk you through every action and expression available for manipulating dates, and show you exactly how to reformat date strings so they play nicely with Power Automate. You can read up about ISO 8601 here but ultimately it means [YYYY]-[MM]-[DD], I explain how to repurpose your date time string below - click here ...