Displaying 1 result from an estimated 1 matches for "stock_symbol".
2012 Oct 10
3
How to replicate SAS by group processing in R
Hello,
I am trying to re-code all my programs from SAS into R.
In SAS I use the following code:
proc sort data=upper;
by tdate stock_symbol expire strike;
run;
data upper1;
set upper;
by tdate stock_symbol expire strike;
if first.expire then output;
rename strike=astrike;
run;
on the following data set:
tdate stock_symbol expiration strike
9/11/2012 C 9/16/2012 11
9/11/2012 C 9/16/2012...