10-30-2012 02:56 PM
code Hi guys,
I was wondering if anyone knew how to create a new variable by performing a simple mathematical operation on an existing column.
I've shown the operation im trying to do in the NEW COLUMN):
EXISTING COLUMN NEW COLUMN
-5 (-5) - (-1)
7 ( 7) - (-5)
-3 (-3) - ( 7)
I basically need to create a new column that subtracts existing observation #1 from #2, existing observation #2 from #3, and so on...
Any ideas as to how I can write a code for this?
Thanks in advance.
10-30-2012 03:08 PM
Also note ... we use LAG quite often, so often that we might forget about:
new_column = dif(EXISTING_COLUMN);