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Power Query Cookbook

You're reading from   Power Query Cookbook Use effective and powerful queries in Power BI Desktop and Dataflows to prepare and transform your data

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Product type Paperback
Published in Oct 2021
Publisher Packt
ISBN-13 9781800569485
Length 412 pages
Edition 1st Edition
Languages
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Author (1):
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Andrea Janicijevic Andrea Janicijevic
Author Profile Icon Andrea Janicijevic
Andrea Janicijevic
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Table of Contents (12) Chapters Close

Preface 1. Chapter 1: Getting Started with Power Query 2. Chapter 2: Connecting to Fetch Data FREE CHAPTER 3. Chapter 3: Data Exploration in Power Query 4. Chapter 4: Reshaping Your Data 5. Chapter 5: Combining Queries for Efficiency 6. Chapter 6: Optimizing Power Query Performance 7. Chapter 7: Leveraging the M Language 8. Chapter 8: Adding Value to Your Data 9. Chapter 9: Performance Tuning with Power BI Dataflows 10. Chapter 10: Implementing Query Diagnostics 11. Other Books You May Enjoy

Invoking custom functions

Power Query offers you the ability to enrich existing tables with additional columns in many different ways, as you have seen in previous recipes, but it also allows you to use custom functions defined as expressions that take some variables as inputs to return a result value. In this recipe, we will see how to create a function, define function parameters, and invoke that function to generate an output.

Getting ready

For this recipe, you need to download the FactResellerSales CSV file.

In this example, we will refer to the C:\Data folder.

How to do it…

Once you open your Power BI Desktop application, you are ready to perform the following steps:

  1. Click on Get data and select the Text/CSV connector.
  2. Browse to your local folder where you downloaded the FactResellerSales CSV file and open it. The following window with a preview of the data will pop up; click on Transform Data:

    Figure 8.36 – CSV data preview

  3. Now, right...
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