Hi! I used data merge to match two tables with a ratio of 1:4, but the merged table presented a ratio of 1:6 or even more. I would like to only keep the first 4 rows for each case ID. How could I do it?   Here are the codes that I used for data merge:   proc sql ; create view _controls as select control_ID,agegrp, sex, A, B, C, rand('uniform') as random1, year from &controls order by year,agegrp, sex, A, B, C,random1; quit; data _cases; set &cases; do rep=1 to 4; random2=rand('uniform'); output; end; keep case_id year agegrp sex A B C rep random2; run; proc sort data=_cases; by year agegrp sex A B C rep random2; run; data &dataout &missing; merge _cases(in=in1) _controls(in=in2); by year agegrp sex A B C; if in1=1 and in2=1 then output &dataout; else if in1=1 and in2=0 then output &missing; run; proc sort data=&dataout; by case_id; run;  then the merged table looks like this:   control_id        case_id    rep   0001                      1             1 0002                     1             2 0003                    1              3 0004                      1            4 0005                    1               4 0006                    1              4 0007                    2              1 0008                   2               2 0009                  2                3 0010                 2                   4 0011                  2                     4 0012                  3                   1   I only want the first 4 rows for each unique case_id.   Thanks!         ... View more

Hi! I am running an exact-matching using the greedy algorithm. I ran the macro code that I found it online and there was the error "insufficient memory to data step program. The SAS system stopped processing this step because of insufficient memory."  I doubled my sas memory to 4g but the error persisted.    I stumbled upon a post detailing a similar issue at this link: https://communities.sas.com/t5/SAS-Programming/Hash-object-with-Insufficient-memory-to-execute-data-step/td-p/440515  As a SAS beginner, I find myself unable to modify my code effectively to reduce the memory demands of the hash object. Any suggestions or coding help would be highly appreciated!   Here is the code: %MACRO MATCH(CASE=,CONTROL=,IDCA=,IDCO=,MVARS=,WTS=,DMAXK=,DMAX=, NCONTLS=1, TIME=, METHOD=,SEEDCA=,SEEDCO=,MAXITER=100000,PRINT=y, OUT=__OUT,OUTNMCA=__NMCA,OUTNMCO=__NMCO,MINCONT=,MAXCONT=); %LET BAD=0; %IF %LENGTH(&CASE)=0 %THEN %DO; %PUT ERROR: NO CASE DATASET SUPPLIED; %LET BAD=1; %END; %IF %LENGTH(&CONTROL)=0 %THEN %DO; %PUT ERROR: NO CONTROL DATASET SUPPLIED; %LET BAD=1; %END; %IF %LENGTH(&IDCA)=0 %THEN %DO; %PUT ERROR: NO IDCA VARIABLE SUPPLIED; %LET BAD=1; %END; %IF %LENGTH(&IDCO)=0 %THEN %DO; %PUT ERROR: NO IDCO VARIABLE SUPPLIED; %LET BAD=1; %END; %IF %LENGTH(&MVARS)=0 %THEN %DO; %PUT ERROR: NO MATCHING VARIABLES SUPPLIED; %LET BAD=1; %END; %IF %LENGTH(&WTS)=0 %THEN %DO; %PUT ERROR: NO WEIGHTS SUPPLIED; %LET BAD=1; %END; %IF %UPCASE(&METHOD)=GREEDY %THEN %DO; %IF %LENGTH(&SEEDCA)=0 %THEN %DO; %PUT ERROR: NO SEEDCA VALUE SUPPLIED; %LET BAD=1; %END; %IF %LENGTH(&SEEDCO)=0 %THEN %DO; %PUT ERROR: NO SEEDCO VALUE SUPPLIED; %LET BAD=1; %END; %END; %IF %LENGTH(&OUT)=0 %THEN %DO; %PUT ERROR: NO OUTPUT DATASET SUPPLIED; %LET BAD=1; %END; %IF %UPCASE(&METHOD)^=GREEDY & %UPCASE(&METHOD)^=OPTIMAL %THEN %DO; %PUT ERROR: METHOD MUST BE GREEDY OR OPTIMAL; %LET BAD=1; %END; %IF (&MINCONT= AND &MAXCONT^= ) OR (&MINCONT^= AND &MAXCONT= ) %THEN %DO; %PUT ERROR: MINCONT AND MAXCONT MUST BOTH BE SPECIFIED; %LET BAD=1; %END; %LET NVAR=0; %DO %UNTIL(%SCAN(&MVARS,&NVAR+1,' ')= ); %LET NVAR=%EVAL(&NVAR+1); %END; %LET NWTS=0; %DO %UNTIL(%QSCAN(&WTS,&NWTS+1,' ')= ); %LET NWTS=%EVAL(&NWTS+1); %END; %IF &NVAR^= &NWTS %THEN %DO; %PUT ERROR: #VARS MUST EQUAL #WTS; %LET BAD=1; %END; %LET NK=0; %IF %QUOTE(&DMAXK)^= %THEN %DO %UNTIL(%QSCAN(&DMAXK,&NK+1,' ')= ); %LET NK=%EVAL(&NK+1); %END; %IF &NK>&NVAR %THEN %LET NK=&NVAR; %DO I=1 %TO &NVAR; %LET V&I=%SCAN(&MVARS,&I,' '); %END; %IF &NWTS>0 %THEN %DO; DATA _NULL_; %DO I=1 %TO &NWTS; %LET W&I=%SCAN(&WTS,&I,' '); IF &&W&I<0 THEN DO; PUT 'ERROR: WEIGHTS MUST BE NON-NEGATIVE'; CALL SYMPUT('BAD','1'); END; %END; RUN; %END; %IF &NK>0 %THEN %DO; DATA _NULL_; %DO I=1 %TO &NK; %LET K&I=%SCAN(&DMAXK,&I,' '); IF &&K&I<0 THEN DO; PUT 'ERROR: DMAXK VALUES MUST BE NON-NEGATIVE'; CALL SYMPUT('BAD','1'); END; %END; RUN; %END; %MACRO DIJ; %DO I=1 %TO &NVAR-1; &&W&I*ABS(__CA&I-__CO&I) + %END; &&W&NVAR*ABS(__CA&NVAR-__CO&NVAR); %MEND DIJ; %MACRO MAX1; %IF &DMAX^= %THEN %DO; & __D<=&DMAX %END; %DO I=1 %TO &NK; & ABS(__CA&I-__CO&I)<=&&K&I %END; %MEND MAX1; %MACRO MAX2; %IF &DMAX= & &NK=0 %THEN %DO; %IF &time^= %then %do; if __cotime>__catime then %end; output; %end; %IF &DMAX^= & &NK=0 %THEN %DO; IF _COST_<=&DMAX %if &time^= %then %do; & __cotime>__catime %end; THEN OUTPUT; %END; %IF &DMAX= & &NK>0 %THEN %DO; IF ABS(__CA1-__CO1)<=&K1 %DO I=2 %TO &NK; & ABS(__CA&I-__CO&I)<=&&K&I %END; %if &time^= %then %do; & __cotime>__catime %end; THEN OUTPUT; %END; %IF &DMAX^= & &NK>0 %THEN %DO; IF _COST_<=&DMAX %DO I=1 %TO &NK; & ABS(__CA&I-__CO&I)<=&&K&I %END; %if &time^= %then %do; & __cotime>__catime %end; THEN OUTPUT; %END; %MEND MAX2; %MACRO LBLS; %DO I=1 %TO &NVAR; __CA&I="&&V&I/CASE" __CO&I="&&V&I/CONTROL" __DIF&I="&&V&I/ABS. DIFF " __WT&I="&&V&I/WEIGHT" %END; %MEND LBLS; %MACRO VBLES; %DO I=1 %TO &NVAR; __DIF&I %END; %DO I=1 %TO &NVAR; __CA&I __CO&I %END; %MEND VBLES; %MACRO GREEDY; %GLOBAL BAD2; DATA __CASE; SET &CASE; %DO I=1 %TO &NVAR; %LET MISSTEST=%SCAN(&MVARS,&I,' '); IF &MISSTEST=. THEN DELETE; %END; %IF &TIME^= %THEN %DO; IF &TIME=. THEN DELETE; %END; DATA __CASE; SET __CASE END=EOF; KEEP __IDCA __CA1-__CA&NVAR __R &mvars %if &time^= %then %do; __catime %end; ; __IDCA=&IDCA; %if &time^= %then %do; __catime=&time; %end; %DO I=1 %TO &NVAR; __CA&I=&&V&I; %END; SEED=&SEEDCA; __R=RANUNI( SEED ); IF EOF THEN CALL SYMPUT('NCA',_N_); PROC SORT; BY __R __IDCA; DATA __CONT; SET &CONTROL; %DO I=1 %TO &NVAR; %LET MISSTEST=%SCAN(&MVARS,&I,' '); IF &MISSTEST=. THEN DELETE; %END; %IF &TIME^= %THEN %DO; IF &TIME=. THEN DELETE; %END; DATA __CONT; SET __CONT END=EOF; KEEP __IDCO __CO1-__CO&NVAR __R &mvars %if &time^= %then %do; __cotime %end; ; __IDCO=&IDCO; %if &time^= %then %do; __cotime=&time; %end; %DO I=1 %TO &NVAR; __CO&I=&&V&I; %END; SEED=&SEEDCO; __R=RANUNI( SEED ); IF EOF THEN CALL SYMPUT('NCO',_N_); RUN; %LET BAD2=0; %IF &NCO < %EVAL(&NCA*&NCONTLS) %THEN %DO; %PUT ERROR: NOT ENOUGH CONTROLS TO MAKE REQUESTED MATCHES; %LET BAD2=1; %END; %IF &BAD2=0 %THEN %DO; PROC SORT; BY __R __IDCO; DATA __MATCH; KEEP __IDCA __CA1-__CA&NVAR __DIJ __MATCH __CONT_N %if &time^= %then %do; __catime __cotime %end; ; ARRAY __USED(&NCO) $ 1 _TEMPORARY_; DO __I=1 TO &NCO; __USED(__I)='0'; END; DO __I=1 TO &NCONTLS; DO __J=1 TO &NCA; SET __CASE POINT=__J; __SMALL=.; __MATCH=.; DO __K=1 TO &NCO; IF __USED(__K)='0' THEN DO; SET __CONT POINT=__K; __D=%DIJ IF __d^=. & (__SMALL=. | __D<__SMALL) %MAX1 %if &time^= %then %do; & __cotime > __catime %end; THEN DO; __SMALL=__D; __MATCH=__K; __DIJ=__D; __CONT_N=__I; END; END; END; IF __MATCH^=. THEN DO; __USED(__MATCH)='1'; OUTPUT; END; END; END; STOP; DATA &OUT; SET __MATCH; SET __CONT POINT=__MATCH; KEEP __IDCA __IDCO __CONT_N __DIJ __CA1-__CA&NVAR __CO1-__CO&NVAR __DIF1-__DIF&NVAR __WT1-__WT&NVAR %if &time^= %then %do; __catime __cotime %end; ; LABEL __IDCA="&IDCA/CASE" __IDCO="&IDCO/CONTROL" %if &time^= %then %do; __catime="&time/CASE" __cotime="&time/CONTROL" %end; __CONT_N='CONTROL/NUMBER' __DIJ='DISTANCE/D_IJ' %LBLS; %DO I=1 %TO &NVAR; __DIF&I=abs(__CA&I-__CO&I); __WT&I=&&W&I; %END; %END; %MEND GREEDY; %IF &BAD=0 %THEN %DO; %IF %UPCASE(&METHOD)=GREEDY %THEN %DO; %GREEDY %END; %ELSE %DO; %OPTIMAL %END; %IF &BAD2=0 %THEN %DO; PROC SORT DATA=&OUT; BY __IDCA __CONT_N; proc sort data=__case; by __IDCA; data &outnmca; merge __case &out(in=__inout where=(__cont_n=1)); by __idca; if __inout=0; **non-matches; proc sort data=__cont; by __IDCO; proc sort data=&out; by __IDCO; data &outnmco; merge __cont &out(in=__inout); by __idco; if __inout=0; **non-matched controls; proc sort data=&out; by __IDCA; **re-sort by case id; %if %upcase(&print)=Y %then %do; PROC PRINT data=&out LABEL SPLIT='/'; VAR __IDCA __IDCO __CONT_N %if &time^= %then %do; __catime __cotime %end; __DIJ %VBLES; sum __dij; title9'Data listing for matched cases and controls'; footnote "match macro: case=&case control=&control idca=&idca idco=&idco"; footnote2 " mvars=&mvars wts=&wts dmaxk=&dmaxk dmax=&dmax ncontls=&ncontls"; %if &time^= %then %do; footnote3"time=&time method=&method seedca=&seedca seedco=&seedco"; %end; %else %do; footnote3" method=&method seedca=&seedca seedco=&seedco"; %end; footnote4" out=&out outnmca=&outnmca outnmco=&outnmco"; run; title9'Summary data for matched cases and controls'; proc means data=&out n mean sum min max; class __cont_n; var __dij %if &nvar >=2 %then %do; __dif1-__dif&nvar __ca1-__ca&nvar %if &time^= %then %do; __catime %end; __co1-__co&nvar %if &time^= %then %do; __cotime %end; ; %end; %else %do; __dif1 __ca1 %if &time^= %then %do; __catime %end; __co1 %if &time^= %then %do; __cotime %end; ; %end; run; proc means data=&outnmca n mean sum min max; var &mvars; title9'Summary data for NON-matched cases'; run; proc means data=&outnmco n mean sum min max; var &mvars; title9'Summary data for NON-matched controls'; run; %end; %END; %END; title9; footnote; run; %MEND MATCH; %match(case=match.trans20_ccaea_case, control=match.ccae20_controls02, idca=MATCHID, idco=ENROLID, ncontls=3, mvars=AGE, maxiter=1, wts=1, dmaxk=0, out=match, method=greedy,seedca=2,seedco=2);   ... 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