Increasing DAX Readability

DAX Code Readability is a key aspect of working with DAX, a formula language that Microsoft developed to help data analysts enrich their data sets and extract useful information from raw data. However, DAX code snippets often contain nested function calls, which can challenge beginners to understand. Therefore, to improve DAX code readability, developers use variables to break the code into smaller, more manageable units. In this blog, you will learn how to use variables to enhance code readability and simplify debugging.

Improving code Readability:

To see how variables can be used to increase readability:

1. First, right-click on the All Measures table.
2. Next, click on New Measure.

Measure tools open.

3. Type the following expression in the formula bar and press Enter.

In this expression:

• Only the products in the product table that belong to the category of “Bikes” and have a list price greater than 2500 are filtered.

4. Next, click on the Card visual in the Visualization Pane.

5. Then, drag and drop “No of Premium Bikes (CM)” from the All Measures table to the Fields.

   

Notice that we have 13 premium bikes in our database. This result is simple; however, the code consists of nested DAX functions, which may not be that easy to understand and comprehend.

Let’s get the same results by first breaking down the code into smaller steps and then increasing code readability by assigning variable names at different steps of the calculation.

6. Right click on No of Premium Bikes (CM) in the All Measures table.

Measure tools open.

7. Erase the existing code.
8. Type the following code in the formula bar and press Enter.

In the Expression:

• First of all, the List Price for the Premium bikes is defined and the value is stored in a variable PremiumBikesListPrice.
• After this, a virtual table of products is created where the product category is “Bikes”. This variable is stored in a variable name BikesCategoryProducts.
• As the third step, a table of the products from the BikesCategoryProducts that have the List Price greater than PremiumBikesListPrice is evaluated and stored in PremiumBikeCategoryProducts.
• Finally, the total rows in the PremiumBikeCategoryProducts are evaluated.

Notice the value in the card visual is still the same. However, the logic behind the calculation is much easier to understand.

Variables for debugging:

You can also change the variables after return. This helps to debug code.

9. Right click on No of Premium Bikes (CM) in the All Measures table.

Measure tools open.

10. Replace the PremiumBikeCategoryProducts in the argument of COUNTROWS() with BikesCategoryProducts.

Notice the change in the value of card visual.

Final Thoughts on DAX Code Readability:

Users use variables in DAX to improve code readability, make code debugging easier, and reduce code complexity. The DAX engine evaluates the variables only once during code execution, which makes the code faster and more readable. This blog provides a step-by-step guide on how users can use variables to improve code readability and perform code debugging.

Are you looking for an instructor-led Power BI or Power Apps training in Australia? We provide classroom as well as online live trainings for the following courses:

• Power BI Essentials
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• DAX Essentials
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