create series of macro variables in form YYMM from 2 months before &start until &end

[Ronein]

Hello

I want to create series of macro variables in form YYMM  from 2 months before &start until &end

In this example start=1901  end=1903 so I want to create series of macro varaibles:

m0=1811

m1=1812

m2=1901

m3=1902

m4=1903

However, in the following code I get all macro parameter values equal 1903.

What is the mistake in the logic please?

%let start=1901;
%let end=1903;


%let date_start=%sysfunc(inputn(&start.,yymmn4.));
%let date_end=%sysfunc(inputn(&end.,yymmn4.));
%put &date_start.  ;/*21550*/
%put &date_end. ; /*21609*/


data _null_;
n1=intck('month',&date_start.,&date_end.);
n2=n1+2;
call symput("n1",trim(left(n1)));
call symput("n2",trim(left(n2)));
run;
%put &n1;
%put &n2;

%macro months;
%do i=-2 %to &n1.;
%do j=0 %to &n2.;
m&j.=put(intnx('month',&date_start.,&i.),yymmn4.);
call symput("m&j",trim(left(m&j.)));
%end;
%end;
%mend;

data aaa;
%months;
run;

%put &&m&n2;
%put &m0;

[Kurt_Bremser · Accepted solution]

You are massively overcomplicating things by abusing the poor macro processor.

Such things are easily done in one simple data step:

%let start=1901;
%let end=1903;

data control;
start = intnx('month',input("&start",yymmn4.),-2,'b');
end = input("&end.",yymmn4.);
length month $4;
m = 0;
do until (start > end);
  month = put(start,yymmn4.);
  call symputx(cats('M',m),month);
  output;
  m + 1;
  start = intnx('month',start,1,'b');
end;
keep month;
run;

%put &m0 &m1 &m2 &m3 &m4;

proc print data=control noobs;
run;

Log excerpt:

42         %put &m0 &m1 &m2 &m3 &m4;
1811 1812 1901 1902 1903

Result of print:

month

1811 
1812 
1901 
1902 
1903 

I created the dataset because data has to be kept in datasets, not unwieldy macro variable lists. The control dataset can easily be used to create dynamic code with call execute.

[Ronein]

Perfect solution.

Thank you.

I am still interested to know what is the error in my code

[Kurt_Bremser]

---

@Ronein wrote:

Perfect solution.

Thank you.

I am still interested to know what is the error in my code

---

Your use of two nested %do loops. When the outer loop reaches 1903, the inner loop overwrites all variables.

Even that logic does not need any macro code at all:

data aaa;
array m {%eval(&n2.+1)} m0-m&n2.;
format m0-m&n2. yymmn4.;
do i = 0 to &n2.;
  m{i+1} = intnx('month',&date_start.,i-2);
end;
drop i;
run;

Maxim 11

Maxim 11

Maxim 11

[ballardw]

I believe nearly 2 years ago when you started posting and were using "dates" in this form YYMM I mentioned that actually using a date value and using an appropriate format to display the date would be easier in the long run.

I am not sure but I suspect this is at least the 20th post you have regarding manipulating dates in this non-date form.

Note that the first thing you have to do each an every time is build a date value to increment or manipulate things.

I have not seen anything where use of YYMM appearing numeric values has made any of your tasks simpler or easier to follow.