Wednesday, January 15, 2025

Power Query Function Signatures Explained: A Beginner's Guide to IntelliSense




When you're working with Power Query's M code, you might notice that when you start typing a function, a small pop-up (called IntelliSense) appears, showing you how to use that function. This pop-up shows a "function signature," which is like a quick instruction manual for the function.

List.Transform
List.Transform(list as list, transform as function) as list
What does it mean when you see something like this.

Part 1 of the code:



list as list: This means the first thing you need is a list (a collection of items like numbers or text).




























Part 2 of the code:




transform as function: This means the second thing you need is a function (a rule or formula) that tells how to change each item in the list.
































Part 3 of the code:















This visually connects the idea that you're taking a list, applying a rule, and getting a new list as a result.