dear RW9, thanks for your attention, here some clarifications: - I highlighted in bold what is my crucial point, I would like to automatize this part, not just for revenue and expenses but for n variables, my issue is not december! If jan and feb is misleading you can overwrite with peaches and lemons or x and y, the point is that I would like to subtract all the numeric variables of one data set to the ones of another one, assuming that both have an identical structure (exactly the same variables). E.g. like a matrix operation in python. - It does not make a difference if I have two data set with the identical structure or two data sets with the identical structure appended with two different key to distinguish the two of them. You can consider your data set or what you got as have1 running my script as the starting point, as you wish. Still my point is not to write my have1 in a better way but how to get from it to want, i.e. to automatize what I highlighted in bold. Thanks again for your support. BRs, SH.
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