I am processing a dataset, the contents of which I do not know in advance. My target SAS instance is 9.3, and I cannot use SQL as that has certain 'reserved' names (such as "user") that cannot be used as column names.
The puzzle looks like this:
data _null_;
set some.dataset; file somefile;
/* no problem can even apply formats */
put name age;
/* how to do this without making new vars? */
put somefunc(name) max(age);
run;
I can't put var1=somefunc(name); put var1; as that may clash with a source variable named var1.
I'm guessing the answer is to make some macro function that will read the dataset header and return me a "safe" (non-clashing) variable, or an fcmp function in a format, but I thought I'd check with the community to see - is there some "old school" way to outPUT directly from a function, in a data step?
Temporary array?
34 data _null_;
35 set sashelp.class;
36 array _n[*] _numeric_;
37 array _f[3] _temporary_;
38 put _n_ #;
39 do _n_ = 1 to dim(_f);
40 _f[_n_] = log(_n[_n_]);
41 put _f[_n_]= #;
42 end;
43 put ;
44 run;
1 _f[1]=2.6390573296 _f[2]=4.2341065046 _f[3]=4.7229532216
2 _f[1]=2.5649493575 _f[2]=4.0342406382 _f[3]=4.4308167988
3 _f[1]=2.5649493575 _f[2]=4.1789920363 _f[3]=4.5849674787
4 _f[1]=2.6390573296 _f[2]=4.1399550735 _f[3]=4.6298627986
5 _f[1]=2.6390573296 _f[2]=4.1510399059 _f[3]=4.6298627986
6 _f[1]=2.4849066498 _f[2]=4.0483006237 _f[3]=4.4188406078
7 _f[1]=2.4849066498 _f[2]=4.091005661 _f[3]=4.4367515344
8 _f[1]=2.7080502011 _f[2]=4.1351665567 _f[3]=4.7229532216
9 _f[1]=2.5649493575 _f[2]=4.1351665567 _f[3]=4.4308167988
The PUT statement does not accept a function invocation as a valid item for output.
A DATA step does not do columnar functions as you indicated with max(age) (so it would be even less likely to use such a function in PUT ;-)
Avoid name collisions
My recommendation is to use a variable name that is highly unlikely to collide.
_temp_001 = somefunc(<var>);
_temp_002 = somefunc2(<var2>);
put _temp_001 _temp_002;
drop _temp_:;
or
%let tempvar = _%sysfunc(rand(uniform, 1e15),z15.);
&tempvar = somefunc(<var>);
put &tempvar;
drop &tempvar;
%symdel tempvar;
Repurpose
You can re-purpose any automatic variable that is not important to the running step. Some omni-present candidates include:
numeric variables:
_n_
_iorc_
_threadid_
_nthreads_
first.<any-name> (only tweak after first. logic associated with BY statement)
last.<any-name>
character variables:
_infile_ (requires an empty datalines;)
_hostname_
avoid
_file_
_error_
I think you would be pretty safe choosing some unlikely to collide names. An easy way to generate these and still make the code somewhat readable would be to just hash a string to create a valid SAS varname and use a macro reference to make the code readable. Something like this:
%macro get_low_collision_varname(iSeed=);
%local try cnt result;
%let cnt = 0;
%let result = ;
%do %while ("&result" eq "");
%let try = %sysfunc(md5(&iSeed&cnt),hex32.);
%if %sysfunc(anyalpha(%substr(&try,1,1))) gt 0 %then %do;
%let result = &try;
%end;
%let cnt = %eval(&cnt + 1);
%end;
&result
%mend;
The above code takes a seed string and just adds a number to the end of it. It iterates the number until it gets a valid SAS varname as output from the md5() function. You could even then test the target dataset name to make sure the variable doesn't already exist. If it does build that logic into the above function.
Test it:
%let my_var = %get_low_collision_varname(iSeed=this shouldnt collide);
%put &my_var;
data _null_;
set sashelp.class;
&my_var = 1;
put _all_;
run;
Results:
Name=Alfred Sex=M Age=14 Height=69 Weight=112.5 C34FD80ED9E856160E59FCEBF37F00D2=1 _ERROR_=0 _N_=1
Name=Alice Sex=F Age=13 Height=56.5 Weight=84 C34FD80ED9E856160E59FCEBF37F00D2=1 _ERROR_=0 _N_=2
This doesn't specifically answer the question of how to achieve it without creating new varnames, but it does give a practical workaround.
This question already has an answer here:
Prompt or Macro Variables used in calculations
(1 answer)
Closed 4 years ago.
I have a data set like this;
DATA work.faminc;
INPUT famid faminc1-faminc12 ;
CARDS;
1 3281 3413 3114 2500 2700 3500 3114 3319 3514 1282 2434 2818
2 4042 3084 3108 3150 3800 3100 1531 2914 3819 4124 4274 4471
3 6015 6123 6113 6100 6100 6200 6186 6132 3123 4231 6039 6215
;
RUN;
I can create a variable and do some stuff with it like,
%let N=12;
DATA faminc1b;
SET faminc ;
ARRAY Afaminc(12) faminc1-faminc12 ;
ARRAY Ataxinc(&N) taxinc1-taxinc&N ;
DO month = 1 TO &N;
Ataxinc(month) = Afaminc(month) * .10 ;
END;
RUN;
But I also want to divide every family income to the one before it.
The result should be like faminc1/faminc2 - faminc2/faminc3 - faminc3/faminc4...
So main problem is how to use arithmetic (+,-,*,/) operators to the "N" variable which i have created.
When I tried to simply do this, it doesnt work;
%let N=12;
DATA faminc1b;
SET faminc ;
ARRAY Afaminc(12) faminc1-faminc12 ;
ARRAY Afamdiv(&N) famdiv1-famdiv&N ;
DO month = 1 TO &N+1;
Afamdiv(month) = faminc&N/faminc&N+1 ;
END;
RUN;
Thanks for the help.
I am not exactly sure what you want to achieve, so i can only answer your question regarding an operation on a macrovariable, to get your sample working you should put it in a seperate macro, then you can do the eval function on your macrovariable to add 1.
But as far as i can see, you must use month as your loopingvariable and not N, also you have to stop at 11, because you dont have a variable 13 to divide with variable 12.
%let N=12;
%macro calc;
DATA faminc1b;
SET faminc ;
ARRAY Afaminc(12) faminc1-faminc12 ;
ARRAY Afamdiv(&N) famdiv1-famdiv&N ;
%DO month = 1 %TO %eval(&N-1);
Afamdiv(&month) = faminc&month/faminc%eval(&month+1) ;
%END;
RUN;
%mend;
%calc;
You do not need to use the macro variable for anything other than to define the upper bound on your varaible list.
Everything else you can do with normal SAS code. Use the DIM() function to find the upper bound arrays. Use the arrays in your calculations. Not sure why you are hardcoding one upper bound and using the macro variable for the other, but if they can be different then you need to consider the length of both arrays to find upper bound for your DO loop.
%let N=12;
DATA faminc1b;
SET faminc ;
ARRAY Afaminc faminc1-faminc12 ;
ARRAY Afamdiv famdiv1-famdiv&N ;
DO month = 1 TO min(dim(afaminc)-1,dim(afamdiv));
Afamdiv(month) = afaminc(month)/afaminc(month+1) ;
END;
RUN;
I'm just starting out in SAS and have run into some troubles. I want to get the number of observations from two data sets and assign those values to existing global macro variables. Then I want to find the smaller of the two. This is my attempt so far:
%GLOBAL nBlue = 0;
%GLOBAL nRed = 0;
%MACRO GetArmySizes(redData=, blueData=);
/* Takes in 2 Army Datasets, and outputs their respective sizes to nBlue and nRed */
data _Null_;
set &blueData nobs=j;
if _N_ =2 then stop;
No_of_obs=j;
call symput("nBlue",j);
run;
data _Null_;
set &redData nobs=j;
if _N_ =2 then stop;
No_of_obs=j;
call symput("nRed",j);
run;
%put &nBlue;
%put &nRed;
%MEND;
%put &nBlue; /* outputs 70 here */
%put &nRed; /* outputs 100 here */
%put %EVAL(min(1,5));
%GetArmySizes(redData=redTeam1, blueData=blueTeam); /* outputs 70\n100 here */
%put &nBlue; /* outputs 70 here */
%put &nRed; /* outputs 100 here */
%MACRO PrepareOneVOneArmies(redData=,numRed=,blueData=,numBlue=);
/* Takes in two army data sets and their sizes, and outputs two new army
data sets with the same number of observations */
%let smallArmy = %eval(min(&numRed,&numBlue));
%put &smallArmy;
%local numOneVOne;
%let numOneVOne = %eval(&smallArmy-%Eval(&nBlue - &nRed));
%put &numOneVOne;
data redOneVOne; set &redData (obs=&numOneVOne);
run;
data blueOneVOne; set &blueData (obs=&numOneVOne);
run;
%MEND;
%PrepareOneVOneArmies(redData=redTeam1,numRed=&nRed,blueData=blueTeam,numBlue=&nBlue);
/* stops executing when program gets to %let smallArmy =... */
redTeam1 is a data set with 100 observations, blueTeam has 70 observations.
I now run into the problem where whenever I call the function "Min" I get:
"ERROR: Required operator not found in expression: min(1,5)"
or
"ERROR: Required operator not found in expression: min(100,70)"
What am I missing?
"Min" seems like a simple enough function. Also, if it matters, I am using the University edition of SAS.
While using functions in macro language you need to wrap the function in %SYSFUNC(). This helps sas delineate from a word that could be min versus a reference to an actual function.
%put %sysfunc(min(1,5));
Not related to your question, but for obtaining the size of a dataset, reading the full data set is an inefficient method. Consider using the dictionary table (SASHELP.VTABLE) instead.
I have a data set with one row for each country and 100 columns (10 variables with 10 data years each).
For each variable I am trying to make a new data set with the three most recent data years for that variable for each country (which might not be successive).
This is what I have so far, but I know its wrong because of the nest loop, and its has same value for recent1 recent2 recent3 however I haven't figured out how to create recent1 recent2 recent3 without two loops.
%macro test();
data Maternal_care_recent;
set wb;
keep country MATERNAL_CARE_2004 -- MATERNAL_CARE_2013 recent_1 recent_2 recent_3;
%let rc = 1;
%do i = 2013 %to 2004 %by -1;
%do rc = 1 %to 3 %by 1;
%if MATERNAL_CARE_&i. ne . %then %do;
recent_&rc. = MATERNAL_CARE_&i.;
%end;
%end;
%end; run; %mend; %test();
You don't need to use a macro to do this - just some arrays:
data Maternal_care_recent;
set wb;
keep country MATERNAL_CARE_2004-MATERNAL_CARE_2013 recent_1 recent_2 recent_3;
array mc {*} MATERNAL_CARE_2004-MATERNAL_CARE_2013;
array recent {*} recent1-recent3;
do i = 2013 to 2004 by -1;
do rc = 1 to 3 by 1;
if mc[i] ne . then do;
recent[rc] = mc[i];
end;
end;
run;
Maybe I don't get your request, but according to your description:
"For each variable I am trying to make a new data set with the three most recent data years for that variable for each country (which might not be successive)" I created this sample dataset with dt1 and dt2 and 2 locations.
The output will be 2 datasets (and generally the number of the variables starting with DT) named DS1 and DS2 with 3 observations for each country, the first one for the first variable, the second one for the second variable.
This is the sample dataset:
data sample_ds;
length city $10 dt1 dt2 8.;
infile datalines dlm=',';
input city $ dt1 dt2;
datalines;
MS,5,0
MS,3,9
MS,3,9
MS,2,0
MS,1,8
MS,1,7
CA,6,1
CA,6,.
CA,6,.
CA,2,8
CA,1,5
CA,0,4
;
This is the sample macro:
%macro help(ds=);
data vars(keep=dt:); set &ds; if _n_ not >0; run;
%let op = %sysfunc(open(vars));
%let nvrs = %sysfunc(attrn(&op,nvars));
%let cl = %sysfunc(close(&op));
%do idx=1 %to &nvrs.;
proc sort data=&ds(keep=city dt&idx.) out=ds&idx.(where=(dt&idx. ne .)) nodupkey; by city DESCENDING dt&idx.; run;
data ds&idx.; set ds&idx.;
retain cnt;
by city DESCENDING dt&idx.;
if first.city then cnt=0; else cnt=cnt+1;
run;
data ds&idx.(drop=cnt); set ds&idx.(where=(cnt<3)); rename dt&idx.=act&idx.; run;
%end;
%mend;
You will run this macro with:
%help(ds=sample_ds);
In the first statement of the macro I select the variables on which I want to iterate:
data vars(keep=dt:); set &ds; if _n_ not >0; run;
Work on this if you want to make this work for your code, or simply rename your variables as DT1 DT2...
Let me know if it is correct for you.
When writing macro code, always keep in mind what has to be done when. SAS processes your code stepwise.
Before your sas code is even compiled, your macro variables are resolved and your macro code is executed
Then the resulting SAS Base code is compiled
Finally the code is executed.
When you write %if MATERNAL_CARE_&i. ne . %then %do, this is macro code interpreded before compilation.
At that time MATERNAL_CARE_&i. is not a variable but a text string containing a macro variable.
The first time you run trhough your %do i = 2013 %to 2004 by -1, it is filled in as MATERNAL_CARE_2013, the second as MATERNAL_CARE_2012., etc.
Then the macro %if statement is interpreted, and as the text string MATERNAL_CARE_1 is not equal to a dot, it is evaluated to FALSE
and recent_&rc. = MATERNAL_CARE_&i. is not included in the code to pass to your compiler.
You can see that if you run your code with option mprint;
The resolution;
options mprint;
%macro test();
data Maternal_care_recent;
set wb;
keep country MATERNAL_CARE_: recent_:;
** The : acts as a wild card here **;
%do i = 2013 %to 2004 %by -1;
if MATERNAL_CARE_&i. ne . then do;
%do rc = 1 %to 3 %by 1;
recent_&rc. = MATERNAL_CARE_&i.;
%end;
end;
%end;
run;
%mend;
%test();
Now, before compilation of if MATERNAL_CARE_&i. ne . then do, only the &i. is evalueated and if MATERNAL_CARE_2013 ne . then do is passed to the compiler.
The compiler will see this as a test if the SAS variable MATERNAL_CARE_1 has value missing, and that is just what you wanted;
Remark:
It is not essential that I moved the if statement above the ``. It is just more efficient because the condition is then evaluated less often.
It is however essential that you close your %ifs and %dos with an %end and your ifs and dos with an end;
Remark:
you do not need %let rc = 1, because %do rc = 1 to 3 already initialises &rc.;
For completeness SAS is compiled stepwise:
The next PROC or data step and its macro code are only considered when the preveous one is executed.
That is why you can write macro variables from a data step or sql select into that will influence the code you compile in your next step,
somehting you can not do for instance with C++ pre compilation;
Thanks everyone. Found a hybrid solution from a few solutions posted.
data sample_ds;
infile datalines dlm=',';
input country $ maternal_2004 maternal_2005
maternal_2006 maternal_2007 maternal_2008 maternal_2009 maternal_2010 maternal_2011 maternal_2012 maternal_2013;
datalines;
MS,5,0,5,0,5,.,5,.,5,.
MW,3,9,5,0,5,0,5,.,5,0
WE,3,9,5,0,5,.,.,.,.,0
HU,2,0,5,.,5,.,5,0,5,0
MI,1,8,5,0,5,0,5,.,5,0
HJ,1,7,5,0,5,0,.,0,.,0
CJ,6,1,5,0,5,0,5,0,5,0
CN,6,1,.,5,0,5,0,5,0,5
CE,6,5,0,5,0,.,0,5,.,8
CT,2,5,0,5,0,5,0,5,0,9
CW,1,5,0,5,0,5,.,.,0,7
CH,0,5,0,5,0,.,0,.,0,5
;
%macro test(var);
data &var._recent;
set sample_ds;
keep country &var._1 &var._2 &var._3;
array mc {*} &var._2004-&var._2013;
array recent {*} &var._1-&var._25;
count=1;
do i = 10 to 1 by -1;
if mc[i] ne . then do;
recent[count] = mc[i];
count=count+1;
end;
end;
run;
%mend;
I'm trying to write robust code to assign values to macro variables. I want the names of the macro variables to depend on values coming from the variable 'subgroup'. So subgroup could equal 1, 2, or 45 etc. and thus have macro variable names trta_1, trta_2, trt_45 etc.
Where I am having difficulty is calling the macro variable name. So instead of calling e.g. &trta_1 I want to call &trta_%SCAN(&subgroups, &k), which resolves to trta_1 on the first iteration. I've used a %SCAN function in the macro variable name, which is throwing up a warning 'WARNING: Apparent symbolic reference TRTA_ not resolved.'. However, the macro variables have been created with values assigned.
How can I resolve the warning? Is there a function I could run with the %SCAN function to get this to work?
data data1 ;
input subgroup trta trtb ;
datalines ;
1 30 58
2 120 450
3 670 3
run;
%LET subgroups = 1 2 3 ;
%PUT &subgroups;
%MACRO test;
%DO k=1 %TO 3;
DATA test_&k;
SET data1;
WHERE subgroup = %SCAN(&subgroups, &k);
CALL SYMPUTX("TRTA_%SCAN(&subgroups, &k)", trta, 'G');
CALL SYMPUTX("TRTB_%SCAN(&subgroups, &k)", trtb, 'G');
RUN;
%PUT "&TRTA_%SCAN(&subgroups, &k)" "&TRTB_%SCAN(&subgroups, &k)";
%END;
%MEND test;
%test;
Using the structure you've provided the following will achieve the result you're looking for.
data data1;
input subgroup trta trtb;
datalines;
1 30 58
2 120 450
3 670 3
;
run;
%LET SUBGROUPS = 1 2 3;
%PUT &SUBGROUPS;
%MACRO TEST;
%DO K=1 %TO 3;
%LET X = %SCAN(&SUBGROUPS, &K) ;
data test_&k;
set data1;
where subgroup = &X ;
call symputx(cats("TRTA_",&X), trta, 'g');
call symputx(cats("TRTB_",&X), trtb, 'g');
run;
%PUT "&&TRTA_&X" "&&TRTB_&X";
%END;
%MEND TEST;
%TEST;
However, I'm not sure this approach is particularly robust. If your list of subgroups changes you'd need to change the 'K' loop manually, you can determine the upper bound of the loop by dynamically counting the 'elements' in your subgroup list.
If you want to call the macro variables you've created later in your code, you could a similar method.
data data2;
input subgroup value;
datalines;
1 20
2 25
3 15
45 30
;
run ;
%MACRO TEST2;
%DO K=1 %TO 3;
%LET X = %SCAN(&SUBGROUPS, &K) ;
data data2 ;
set data2 ;
if subgroup = &X then percent = value/&&TRTB_&X ;
format percent percent9.2 ;
run ;
%END;
%MEND TEST2;
%TEST2 ;
Effectively, you're re-writing data2 on each iteration of the loop.
This should cover your requirements. You can load and unload an array of macro variable without a macro. I have included an alternate method of unloading a macro variable array with a macro for comparison.
Load values into macro variables including Subgroup number within macro variable name e.g. TRTA_45.
data data1;
input subgroup trta trtb;
call symput ('TRTA_'||compress (subgroup), trta);
call symput ('TRTB_'||compress (subgroup), trtb);
datalines;
1 30 58
2 120 450
3 670 3
45 999 111
;
run;
No need for macro to load or refer to macro variables.
%put TRTA_45: &TRTA_45.;
%let Subgroup_num = 45;
%put TRTB__&subgroup_num.: &&TRTB_&subgroup_num.;
If you need to loop through the macro variables then you can use Proc SQL to generate a list of subgroups.
proc sql noprint;
select subgroup
, count (*)
into :subgroups separated by ' '
, :No_Subgroups
from data1
;
quit;
%put Subgroups: &subgroups.;
%put No_Subgroups: &No_Subgroups.;
Use a macro to loop through the macro variable array and populate a table.
%macro subgroups;
data subgroup_data_macro;
%do i = 1 %to &no_subgroups.;
%PUT TRTA_%SCAN(&subgroups, &i ): %cmpres(&TRTA_%SCAN(&subgroups, &i ));
%PUT TRTB_%SCAN(&subgroups, &i ): %cmpres(&TRTB_%SCAN(&subgroups, &i ));
subgroup = %SCAN(&subgroups, &i );
TRTA = %cmpres(&TRTA_%SCAN(&subgroups, &i ));
TRTB = %cmpres(&TRTB_%SCAN(&subgroups, &i ));
output;
%end;
run;
%mend subgroups;
%subgroups;
Or use a data step (outside a macro) to loop through the macro variable array and populate a table.
data subgroup_data_sans_macro;
do i = 1 to &no_subgroups.;
subgroup = SCAN("&subgroups", i );
TRTA = input (symget (compress ('TRTA_'||subgroup)),20.);
TRTB = input (symget (compress ('TRTB_'||subgroup)),20.);
output;
end;
run;
Ensure both methods (within and without a macro) produce the same result.
proc compare
base = subgroup_data_sans_macro
compare = subgroup_data_macro
;
run;