Importing monthly text files from the previous 12 months

[mb402]

Hi!

I would like to learn how to read in and stack files from the previous 12 months all at once. The files are monthly text files with a XX month lag (ex: If I were to run an analysis in October, I would pull files from June if XX=05, but if I were to run an analysis in November, I would pull files from July). I also need to pull files for each of the 12 months prior. All the files have a name like zz_MON_YYYY.txt. 

[Tom]

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@mb402 wrote:

Hi!

I would like to learn how to read in and stack files from the previous 12 months all at once. The files are monthly text files with a XX month lag (ex: If I were to run an analysis in October, I would pull files from June if XX=05, but if I were to run an analysis in November, I would pull files from July). I also need to pull files for each of the 12 months prior. All the files have a name like zz_MON_YYYY.txt. 

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Step one is write the code to read one file.

Then you can make a design decision.  Do you want to write one data step that reads all 12 files at once?  Or read one file at a time and then combine the generated datasets.

For the first option modify the code to read from two files at once. Something like:

filename files ('zz_OCT_2019.txt','zz_SEP_2019.txt');
data want;
   infile files .... ;
....

For the second option write the step that combines two of the files.

data want;
  set month1 month2;
run;

See how to extend the pattern to 12 files.

For the issue of how to generate 12 months just use the INTNX() function.  

data months;
   start=today();
   do offset=0 to -11 by -1 ;
      next_month=intnx('month',start,offset);
      output;
  end;
  format start next_month date9.;
run;