topic Re: How to read file with date stamp for previous day if today's file is missing/not available in New SAS User

How to read file with date stamp for previous day if today's file is missing/not available

bijayadhikar — Wed, 19 Jan 2022 15:47:09 GMT

Is there a way to read file with date stamp for previous day if today's file is missing/not available? I do read file with date with date stamp with macro code as below for current day (or day's file). It does work whether to read to day's file or any previous day (with subtraction in date). However, my question is: how to read yesterday's file IF today's file is missing/not exist.

This is a Unix environment.

%let Date = %sysfunc(date(),Date9.);
%put &Date;
libname dat '/.........../folder_name';

data new;
set dat._&Date._merged_line_list;
run;

Re: How to read file with date stamp for previous day if today's file is missing/not available

Kurt_Bremser — Wed, 19 Jan 2022 15:54:50 GMT

What if neither dataset exists?

Re: How to read file with date stamp for previous day if today's file is missing/not available

ballardw — Wed, 19 Jan 2022 16:12:10 GMT

Basic steps: Determine if the file exists. The SAS function FEXIST does this if used correctly for EXTERNAL files or EXIST to check on the existence of a SAS data set or view.

If that does not exist then generate the name for the "previous day" file. Check if it exists.

When you have verified the file exist then process. If none of the desired files exist then write some output that says so and terminate that portion of your program.

Re: How to read file with date stamp for previous day if today's file is missing/not available

bijayadhikar — Thu, 20 Jan 2022 13:58:16 GMT

@Kurt_Bremser good question, yes it is possible that someday a file may not be available.

@ballardw Thank you for offering this logics. I will try to see if I can figure out.

Re: How to read file with date stamp for previous day if today's file is missing/not available

Kurt_Bremser — Thu, 20 Jan 2022 14:04:14 GMT

So could we rephrase your question as: read the latest dataset available, going back from a certain date (today)?

Or should we, if neither today's and yesterday's dataset is available, issue an error message and terminate?

Re: How to read file with date stamp for previous day if today's file is missing/not available

bijayadhikar — Thu, 20 Jan 2022 16:54:52 GMT

@Kurt_Bremser

Exactly that's what I wanted. Read the latest file from a folder. File name structure is e.g. 19JAN2022_report

Re: How to read file with date stamp for previous day if today's file is missing/not available

Kurt_Bremser — Thu, 20 Jan 2022 19:17:01 GMT

A name that starts with a digit is not valid for SAS datasets; are we talking datasets or files?

Re: How to read file with date stamp for previous day if today's file is missing/not available

bijayadhikar — Mon, 31 Jan 2022 23:55:04 GMT

@Kurt_Bremser

I was talking about datasets (also excel files). With macro date $Date function datasets are created or read. However I am re-thinking as it is not straightforward because I realize that some days files are missing or date gap, so I can leave as is for now.

Thank you all for offering support

Re: How to read file with date stamp for previous day if today's file is missing/not available

Tom — Tue, 01 Feb 2022 03:29:19 GMT

@bijayadhikar wrote:

...

Exactly that's what I wanted. Read the latest file from a folder. File name structure is e.g. 19JAN2022_report

Word of advice, do not use DATE (or MDY or DMY order ) style dates in filenames. They will NOT sort properly.

Use YMD order date strings in names. Then the filenames will sort in chronological order.

Re: How to read file with date stamp for previous day if today's file is missing/not available

Kurt_Bremser — Tue, 01 Feb 2022 07:21:06 GMT

Excel files are NOT SAS datasets.

By defining a LIBNAME for an Excel file, it is possible to use spreadsheets in that file like datasets.

So please describe in detail where you need to apply that date.