Debug tools for M Code

Hi RT8 

Thank you for reaching out to the Microsoft Fabric Community Forum.
 

Power Query (M) does not have a traditional debugger, but it provides powerful built-in tools and techniques to debug effectively.
 

To troubleshoot complex M code:

1. Use intermediate steps in the Advanced Editor to inspect outputs step-by-step.
2. Apply the try...otherwise expression to catch and isolate errors.
3. Use Diagnostics.Trace to log values during execution, especially in recursive or nested functions.

When working with complex or recursive logic:

1. Consider using List.Accumulate as a more efficient and readable alternative to recursion, especially for large datasets.
2. As suggested by lbendlin , List.Generate can also be a powerful approach for building iterative logic in a controlled manner.
   
   

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Thank You!