SPLIT from tall to wide: how to group the resulting columns dynamically?
So I've got a large dt that I'm splitting from TALL to WIDE. This results in a huge qty of columns, all with the header format = "Step#_Parameter_Function".The amount of these columns vary and are never predictable and set, nor are the step #'s or names. How would i be able to then group these columns by Step#? Some sort of loop to scan through the long list of columns, pick out the first Step# an...