Power Query Functionality to hide a field

Hi,

I don't think you need to hide the field, in fact, "hiding field" would be something very strange for power query.

Power Query create a sequence of transformation actions. The later actions don't "break" previous actions.

In your case: You have two columns, you want to create a 3rd calculated column.

Go ahead, create it. The creation of the 3rd column will be one step on the transformation sequence. Later, remove the column you don't want, keep the other two. 

The removal of the column happens after the calculated column was created, so it doesn't affect in any way the calculated column.

However, if what you are looking for is an active formula, which will change the value according to the context of other columns, this shouldn't even be in Power Query, this is something done in the model, using a DAX measure.

Kind Regards,

Dennes