trying to find the variables/set of variables that causes multiple duplicates for id

[bikashten]

Hi all,

I am trying to find the variables or group of variables which cause the duplicates for id in the data during extraction. In my original data set, I have 100 variables and 500 duplicates for id. Here is a sample data set:

data test;
input id x1 x2 x3 x4;
datalines;
1 0 1 3 4
1 1 1 3 4
2 2 4 6 8
2 2 6 6 8 
3 3 3 3 3 
3 3 3 3 3 

;

I want this data set: because id 1 has only discrepancy for x1 and id 2 has discrepancy for x2 so that would like to get table like this. 

id	x1	x2
1	0	1
1	1	1
2	2	4
2	2	6
3	3	3
3	3	3

Thank you for your help!!!

Bikash

[kulbshar]

You may to create a macro and pass variable to it to find duplicates. I have created a macro to do the same on your dummy table & it's working.

data test;
input id x1 x2 x3 x4;
datalines;
1 0 1 3 4
1 1 1 2 3
2 2 4 6 8
2 2 6 5 5
3 3 3 7 3
3 3 3 3 7

;
run;

proc contents
data = test(drop=id)
noprint
out = data_info
(keep = name varnum);
run;

proc sql;
select name into: name1-
from data_info;
quit;

%put &name1 &name2 &name3 &name4;

%macro find_dup_var(tab=,key=,var=);
proc sql noprint;
create table tab&var. as select count(distinct &var.) as &var._cnt from &tab group by &key;
quit;

proc sql;
select "&var." as duplicate_variable from tab&var. having min(&var._cnt) =1;
quit;

%mend find_dup_var;

%macro run1();
%do i=1 %to 4;
%find_dup_var(tab=test,key=id,var=&&name&i.)
%end;

%mend;

%run1;

[Astounding]

Here's an approach for numeric variables.  It can be expanded to include character variables as well if that is important.

data _null_;
   set have (drop=id);
   array nums {*} _numeric_;
   call symputx('n_nums', dim(nums));
   stop;
run;

data _null_;
   if 5=4 then set have (drop=id);
   array nums {&n_nums} _numeric_;
   array lastv {&n_nums} _temporary_;
   array keepyn {&n_nums} $ 1 _temporary_;
   set have end=done;
   by id;
   do _n_=1 to &n_nums;
      if first.id=0 and lastv{_n_} ne nums{_n_} then keepyn{_n_} = 'Y';
      lastv{_n_} = nums{_n_};
   end;
   length keeplist $ 20000;
   if done;
   do _n_=1 to &n_nums;
      if keepyn{_n_} = 'Y' then keeplist = catx(' ', keeplist, vname(nums{_n_}) ) ;
   end;
   call symputx('keeplist', keeplist);
run;

data want;
   set have (keep=id &keeplist);
run;

The code is untested, so you will have to try it.  That's probably a good idea before trying to expand it to include character variables as well.  

Once it is debugged, the major advantage is that it only takes 2 passes through the data to handle everything that needs to be done.

[Ksharp]

data test;
input id x1 x2 x3 x4;
datalines;
1 0 1 3 4
1 1 1 3 4
2 2 4 6 8
2 2 6 6 8 
3 3 3 3 3 
3 3 3 3 3 
;
run;
proc sql;
create table temp as
 select id,count(distinct x1) as x1, count(distinct x2) as x2,
 count(distinct x3) as x3,count(distinct x4) as x4
  from test 
   group by id;
quit;

proc transpose data=temp out=temp1;
by id;
run;
proc sql noprint;
select distinct _name_ into : names separated by ','
from temp1
 where col1>1;

create table want as
 select id,&names from test;
quit;