1. Custom Functions in Power Query
By Yury Tokarev
Perth Modern Excel & Power BI User Group

2. Agenda Build from scratch Connect to a range Retrieve data
Transform before appending
Create a loop

3. What is a Function?

4. Vending machine

5. MAX(1,2)=2

6. Reference to Single Cell
Use function to get value from cell

7. Get Data from Range
Single Cell
Table

8. Dates as parameters

9. Inconsistent Data from Folder
Create Query from single file
Transform – do not set data types
Convert to Function
Create Query from Folder
Place function into new column as second step
Expand records

10. Loop Table Names & Combine Data
Use recursive function
Function arguments: Index, List of Tables, Resulting Table
The function calls itself several times and combines resulting tables

11. Recursive Function Steps
Calculate number of tables in the list
Return combined table if all iterations are done
First iteration: Retrieve data from first table only + Increment Index
Next iterations: retrieve data from other tables and combine + Increment Index

12. Q&A

13. Thank you!