Add variable based on import file name

[dsm]

I have hundreds of comma delimited text files that have two columns and hundreds of thousands of rows, Each file is named after the participant (e.g., 1, 3, 15, etc...). What I need is two-fold, and both may not be possible in the same step.

I'd like to:

1) batch import each file and

2) create a new variable based on each file name. So, I'd like a variable called "subj" that has the value 1 in every row for file 1, and so on...

I've searched around and can't find any information on creating a variable from the import filename. Any advice? 

Thanks!

[Reeza]

FILEVAR option on the INFILE statement. See example 5 in the documentation. 

http://documentation.sas.com/?docsetId=lestmtsref&docsetTarget=n1rill4udj0tfun1fvce3j401plo.htm&docs...

And older walk through

https://support.sas.com/techsup/technote/ts581.pdf

Another option:

https://communities.sas.com/t5/SAS-Communities-Library/How-do-I-write-a-macro-to-import-multiple-tex...

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@dsm wrote:

I have hundreds of comma delimited text files that have two columns and hundreds of thousands of rows, Each file is named after the participant (e.g., 1, 3, 15, etc...). What I need is two-fold, and both may not be possible in the same step.

I'd like to:

1) batch import each file and

2) create a new variable based on each file name. So, I'd like a variable called "subj" that has the value 1 in every row for file 1, and so on...

I've searched around and can't find any information on creating a variable from the import filename. Any advice? 

Thanks!

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[RW9 · Accepted solution]

Do you want all this data combined into one dataset at the end (which if the data is the same would be the best method):

data want (keep=fname a b);
  infile ".../*.csv" filename=fname;
  input a b;
run;

If you want separate ones then, something like:

filename tmp pipe 'dir ".../*.csv" /b';

data _null_;
  infile tmp dlm="¬";
  call execute(cats('data want',put(_n_,best.),'; infile "',_infile_,'"; input a b; run;'));
run;

This would create wantX with X being incremental for each file - mainly to show how to do it.

[dsm]

super helpful, thanks so much!