Retain multiple variables and use subset within do loop

[cool1993]

Hello everyone,

My dataset is the following:

Person	Person_num	Year	Firstyear	Company
A	1	2005	1	aa
A	1	2006	0	aa
A	1	2007	0	aa
A	1	2008	0	aa
A	1	2008	0	bb
A	1	2009	0	aa
A	1	2009	0	bb
B	2	2008	1	cc
B	2	2009	0	dd
B	2	2009	0	cc
B	2	2010	0	dd
B	2	2011	0	dd
B	2	2012	0	dd
C	3	2002	1	ee
C	3	2002	1	ff
C	3	2003	0	ee
C	3	2003	0	ff
C	3	2004	0	ff
C	3	2008	0	ff
C	3	2009	0	ff
C	3	2010	0	ff
C	3	2011	0	ff
C	3	2012	0	ff
C	3	2012	0	gg
C	3	2013	0	ff
C	3	2014	0	ff
D	4	2005	1	hh
D	4	2006	0	hh
D	4	2010	0	ii
D	4	2011	0	ii
D	4	2012	0	ii
D	4	2014	0	jj
D	4	2015	0	jj

The expected outcome is the following:

Person	Person_num	Year	Firstyear	Company	Save	Want
A	1	2005	1	aa	aa	1
A	1	2006	0	aa	aa	0
A	1	2007	0	aa	aa	0
A	1	2008	0	aa	aa	0
A	1	2008	0	bb	aa	0
A	1	2009	0	aa	aa	0
A	1	2009	0	bb	aa	0
B	2	2008	1	cc	cc	1
B	2	2009	0	dd	cc	0
B	2	2009	0	cc	cc	0
B	2	2010	0	dd	dd	1
B	2	2011	0	dd	dd	0
B	2	2012	0	dd	dd	0
C	3	2002	1	ee	{ee, ff}	1
C	3	2002	1	ff	{ee, ff}	1
C	3	2003	0	ee	{ee, ff}	0
C	3	2003	0	ff	{ee, ff}	0
C	3	2004	0	ff	ff	0
C	3	2008	0	ff	ff	0
C	3	2009	0	ff	ff	0
C	3	2010	0	ff	ff	0
C	3	2011	0	ff	ff	0
C	3	2012	0	ff	ff	0
C	3	2012	0	gg	ff	0
C	3	2013	0	ff	ff	0
C	3	2014	0	ff	ff	0
D	4	2005	1	hh	hh	1
D	4	2006	0	hh	hh	0
D	4	2010	0	ii	ii	1
D	4	2011	0	ii	ii	0
D	4	2012	0	ii	ii	0
D	4	2014	0	jj	jj	1
D	4	2015	0	jj	jj	0

The logic behind is the following:

1. If firstyear = 1 then want = 1; 

2. If firstyear = 1, save = {companies}. That is, save include all companies when firstyear = 1. (Is it possible to save multiple variables into the save variable?)

3. If firstyear ne 0 and company = lag(save), then save = lag(save) and want = 0;

    else if the company in save then save = lag(save) and want = 0;

    else if, among the same year observations, there is an observation whose company is equal to the current observation's save variable, then save = lag(save) and want = 0;

    else save = code and want = 1;

My attempt is the following:

data have;
input Person $ Person_num Year Firstyear Company $;
datalines;
A	1	2005	1	aa
A	1	2006	0	aa
A	1	2007	0	aa
A	1	2008	0	aa
A	1	2008	0	bb
A	1	2009	0	aa
A	1	2009	0	bb
B	2	2008	1	cc
B	2	2009	0	dd
B	2	2009	0	cc
B	2	2010	0	dd
B	2	2011	0	dd
B	2	2012	0	dd
C	3	2002	1	ee
C	3	2002	1	ff
C	3	2003	0	ee
C	3	2003	0	ff
C	3	2004	0	ff
C	3	2008	0	ff
C	3	2009	0	ff
C	3	2010	0	ff
C	3	2011	0	ff
C	3	2012	0	ff
C	3	2012	0	gg
C	3	2013	0	ff
C	3	2014	0	ff
D	4	2005	1	hh
D	4	2006	0	hh
D	4	2010	0	ii
D	4	2011	0	ii
D	4	2012	0	ii
D	4	2014	0	jj
D	4	2015	0	jj
;
data want; set have;
do i = 1 to 4;
if person_num = i then do;
 	if firstyear = 1 then want = 1 and save = code; *How can assign multiple variables into the save variable when Person = C;
	if firstyear ne 0 and company = lag(save) then save = lag(save) and want = 0;
	else if company in save then save = lag(save) and want = 0;
	else if; *I have no idea in this part.;
	else want = 1;
end;
end;
run;

[cool1993]

Hello,

I am stuck to solve the difficulty.

I need your knowledge..

The dataset and the expected result("Want variable" is the following:

Person	Year	Company	Want
A	2005	aa	1
A	2006	aa	0
A	2007	aa	0
A	2008	aa	0
A	2008	bb	0
A	2009	aa	0
A	2009	bb	0
B	2008	cc	1
B	2009	dd	0
B	2009	cc	0
B	2010	dd	1
B	2011	dd	0
B	2012	dd	0
C	2002	ee	1
C	2002	ff	1
C	2003	ee	0
C	2003	ff	0
C	2004	ff	0
C	2008	ff	0
C	2009	ff	0
C	2010	ff	0
C	2011	ff	0
C	2012	ff	0
C	2012	gg	0
C	2013	ff	0
C	2014	ff	0
D	2005	hh	1
D	2006	hh	0
D	2010	ii	1
D	2011	ii	0
D	2012	ii	0
D	2014	jj	1
D	2015	jj	0

The logic to determine the "want variable" is like this:

1. if first.person then want = 1; if year = lag(year) and lag(want) = 1 then want = 1;

2. When the want variable =1, I would like to save the company as a new "save variable". (Is it possible to save multiple variables into the save variable?)

3. If the company of current observation equals to the save variable, then want = 0; else if there is an observation which has the same company with the save variable in the same year, then want = 0; else want = 1;

4. And everytime the want variable changes from 0 to 1, I would like to update the save variable to the company with the corresponding value of 1.

If you know an easy way to solve this problem, please let me know.

Thanks for your help.

[Patrick]

@cool1993 

I believe the bit you will be able to do for us:

Provide a fully working SAS data step posted via the running man icon above which creates the sample data and also includes at least your first condition: if first.person then want = 1;

Why is your Want=1 for below case. Which one of your rules applies here?

B

2010

dd

1

I would like to save the company as a new "save variable".

Then please add also a new column save_want to your table with the desired result so we can see what you expect to get.

[Reeza]

Here are instructions on how to provide sample data as a data step:
https://communities.sas.com/t5/SAS-Communities-Library/How-to-create-a-data-step-version-of-your-dat...

[cool1993]

I added the detailed info. and B 2010 dd has the value of 1 by the rule 3.