topic Re: Deleting an internal file in SAS Data Management

Deleting an internal file

Jazzman — Tue, 23 Feb 2016 13:59:46 GMT

Hi, this is (hopefully) a very basic question but I couldn't find an answer on the net. I'm a beginner regarding SAS, so these are my very first steps.

What's the way to delete an "internal" file (i. e. a file in my user directory that I can access over a library)? I know that it is possible to delete any file via a data step with the fdelete function but you need to use the full path to the file, right? What if I'm working with a number of data files in my SAS directory and I want to delete one of them? Is there a possibility do do so just by referencing the internal name of the file (i. e. libraryname.filename without having to include the absolute path)?

Thanks for your help!

(I'm working with SAS Studio/University Edition over a virtual machine, btw.)

Re: Deleting an internal file

data_null__ — Tue, 23 Feb 2016 14:04:50 GMT

PROC DATASETS is used to manage SAS Files. Deletion is just one many tasks PROC DATASETS can do for you.

Re: Deleting an internal file

Kurt_Bremser — Tue, 23 Feb 2016 14:06:36 GMT

Another method is

proc delete data=datasetname(s);
run;

Re: Deleting an internal file

Kurt_Bremser — Tue, 23 Feb 2016 14:07:48 GMT

Still another method is

proc sql;
drop table datasetname;
quit;

Re: Deleting an internal file

RW9 — Tue, 23 Feb 2016 14:57:28 GMT

Well, the chaps above have given you some good advice for removing SAS files - i.e. datasets. Does this cover what your after, or do you mean other types of files? Generally speaking I would be very careful about removing files using any technique - datasets for instance can be overwritten with new datasteps. There is generally speaking, very little need to actually delete a file, most operations will overwrite a file. So why do you need to do this (if the operation fails, or your put the wrong information in you could lose the file completely, or deleting non-SAS files could remove importatnt files.

Re: Deleting an internal file

Kurt_Bremser — Tue, 23 Feb 2016 15:05:13 GMT

Well, one of the reasons to delete a dataset may come from the fact that an overwrite by SAS is not an overwrite. The new dataset is written side-by-side (.lck), and only when the step finishes, the old dataset is deleted and the new one renamed. With big datasets, this may cause a "file is full and may be damaged" error because twice the dataset size is needed.

Also, libraries tend to clutter, and especially when using EG a large number of datasets in a library will take considerable time to display when the library is expanded in the navigation panel.

Re: Deleting an internal file

RW9 — Tue, 23 Feb 2016 15:11:17 GMT

Good point, hadn't thought of that! (I wouldn't recommend it though for learners using UE though).

Re: Deleting an internal file

Reeza — Tue, 23 Feb 2016 15:29:55 GMT

If I have a macro that's generating data sets and looping over a bunch of iterations I may delete datasets to ensure that if there's an error in one loop the results from the previous results are not available.

Re: Deleting an internal file

Jazzman — Tue, 23 Feb 2016 15:54:54 GMT

PROC DELETE is exactly what I was looking for, thanks a lot!