Calculated columns or M?

[JuanSombrero]

Hi all

i only recently started working with power query, and ever since I feel like I have a luxury problem. My typical data set container a file number column which I normally split up with left() and right() into a number of calculated columns in power pivot. Since the only source for this calculation is in the actual data, I could just as well prepare these columns in power query before I load it into my data model. My gut feeling says its better to do it in power query for performance reasonning.

Am I right, and is there any 'best practice' to keep in mind when making such choices?

thx in advance
Juan

 

[Matt Allington]

Yes you are correct. Always always prepare data before loading if you can. Use Calc columns sparingly in the instances you have no choice. This is best practice.