SAS: Most frequent value (Like a MODE) ties solved by recency?

Question

I have data like this:

data mydata;
input ID $ Val $ Date;
datalines;
1  A  2010-12-01 
1  B  2010-12-03 
1  A  2010-12-04 
1  B  2010-12-08
2  X  2009-10-01 
2  X  2009-10-02 
2  Z  2009-10-03 
;
run;

I would like the mode returned where it exists. ID 1, however, doesn't have a true mode. In the case of ties where modes do not exist I would like the most recent Val to break the tie (as in id 1).

Desired OUTPUT:

ID Mode
1  B  
2  X  

I tried proc univariate (which only handles numeric modes, another problem) but this gives the dataset with mode null; which SAS has correct but is not the desired output. I would like to do this in a datastep.

CODE:

proc univariate data=mydata noprint;
class id;
var val;
output out=modetable mode=mode;
run;

OUTPUT:

ID Mode
1  
2  X

Answer 1

use IDgroup from proc means

An example of this statement can be fount in Identifying the Top Three Extreme Values with the Output Statistics

Let us extend the example data a little bit;

data myInput;
    infile datalines dsd delimiter='09'x;
    input 
        @1 ID 1. 
        @4 Val $1. 
        @7 Date yymmdd10.;
    format Date yymmdd10.;
    datalines;
2  X  2009-10-01
2  X  2009-10-02
2  Z  2009-10-03
3  C  2010-10-01
3  B  2010-10-03
3  A  2010-10-04
3  A  2010-12-01
3  B  2010-12-03
3  C  2010-12-04
;
run;

Now let us count the frequency and the last occurence of each ´Val´ for each ´ID´;

proc sql;
    create view myView as 
    select ID, Val, max(Date) as Date format=yymmdd10., count(*) as freq
    from myInput
    group by ID, Val;
run;

And finally, retain one Val for each ID, prefering the more frequent one and within equally frequent ones the most recent one;

proc means data=myView nway noprint;
   class ID;
   output out=myModes(keep= ID Mode)
          idgroup( max(freq Date) out[1] (Val)=Mode);
run;

proc print data=myModes;
run;

The result is;

ID  Mode
2   X
3   C