02-11-2015 06:22 AM
I'd like to understand how to combine obs from different records into a single observation in the output?For example, in sashelp.class or using some of your own input, can anybody demonstrate with a code how to accomplish the same?
1. combine 4,6,and 8 to the 3rd observation?
2. combine 2nd obs, and last observation to 1st obs.
What i really am after is i wanna understand how you look prev once you are past that iteration in the implied datastep loop. Examples i would appreciate is doing the sample in 1. multiple pass and 2. in single pass. Any kind of simple, medium and complex examples will really help.
02-11-2015 06:36 AM
Hi,
Provide some test data and required output. There are many logical methods of looking up observations which fit into many differing scenarios - hash tables, merge statements, have a set in a conditional branch, sub-querying in sql, lag() function, by group processing, arrays etc. Say for instance your first options - combine 4,6,8 to 3rd observation - what does this actually mean. The position of a row in a dataset is purely arbitrary, so if I sort that dataset maybe row 8 will be in position 3. I wouldn't recommend to use arbitrary row number as a means to identify specific data.
If however row 4, 5, 6 contains a id variable for "sum" and row 3 has the id "total" then we could do:
data have;
idvar="not used"; output;
idvar="not used"; output;
idvar="total"; result=.; output;
idvar="sum"; result=4; output;
idvar="sum"; result=3; output;
idvar="sum"; result=6; output;
run;
proc sql;
create table WANT as
select IDVAR,
(select SUM(RESULT) from WORK.HAVE where IDVAR="sum") as RESULT
from WORK.HAVE
where IDVAR="total";
quit;