1. Make Your Code File Driven Methods to let SAS collect file names in your system
Lu Zhang
Beijing, China 1

2. Introduction Background SAS Data-Driven Features
Most of the SAS powerful functions are based on a data-driven approach.
Increased general usability as a result of independence from raw data.
Dynamic output from different data contents.
Fewer parameters. 2

3. Introduction Background Idea Needs Illumination
Data-Driven feature is self proved to be an excellent approach.
To extend it - Let the driven approaches not only based on the data structure but also on the external files.
File driven there it is.
Let SAS communicate with our operating system. 3

4. Introduction Background
How This Idea Serves in Pharmaceutical Industry
To import external data.
To combine output files.
Make our macros more flexible.
Example (SDTM implementation with raw data being external *.csv files)
%mimport(ae.csv);
%mimoort(cm.csv); VS %mimport("folder path");
%mimport(mh.csv);
...
No need to type their names one by one, just tell SAS where they are. 4

5. Introduction Aim of this paper
Two Methods to implement the file driven approach
SAS 'D-' functions.
Using a series of SAS functions including DOPEN, DNUM and DREAD.
Unnamed SAS Pipes
SAS Pipes allows us using DOS commands in Windows system outside SAS. 5

6. Method 1: SAS 'D-' Functions
Descriptions of Functions
How These 'D-' Functions Works
DOPEN
to open a directory and return a directory identifier value.
DNUM
to get the numbers of members in the opened directory.
DREAD
to return the names of each members.
DCLOSE
to close the opened directory to release the thread. 6

7. Method 1: SAS 'D-' Functions
Utilizations of Functions
Utilization of These Functions and Implementation SAS Code
All should be within a data step.
Open a specific path under which our target files are located with DOPEN.
Get the total number of files exist under the path with DNUM.
In a do-loop, get each files' filename with DREAD and assign them to a variable. 7

8. Method 1: SAS 'D-' Functions
Results of Method 1
Result
Source folder
Result data 8

9. Method 1: SAS 'D-' Functions
Utilization
Example (SDTM implementation with raw data being external *.csv files)
%macro mimport(path=);
**Code for collecting file names; …;
%do i=1 %to &k;
**Original code for importing files;
%end;
%mend;

10. Method 2: Unnamed SAS Pipes
Basic Introduction
Basic Introduction of Pipes and Dos Commands
Implementing dos commands within SAS like X statement.
More than X statement, SAS pipes are dynamic connections.
With following SAS code we can look up for dos commands
Example (SAS code to look up for dos commands)
filename indata pipe 'help';
data help;
infile indata truncover;
input help $300.;
if _n_ ne 1;
run; 10

11. Method 2: Unnamed SAS Pipes
Utilization of SAS Pipes to Read File Names
Implementation SAS Code
Example
filename indata pipe 'dir "c:\external data\*.csv" /b';
data flst;
format fname $30.;
infile indata truncover;
input fname;
call symput("n_file",_n_);
run;
filename indata clear; 11

12. Method 2: Unnamed SAS Pipes
Results With Same Case
Result By Using SAS Pipes
Exactly same, but less heavy code and simpler logic compared with using 'D-' functions. 12

13. Method 2: Unnamed SAS Pipes
Further Extended
UNC Path
UNC - Universal Naming Convention.
Many companies have their global SAS working environment in which network shares often being used.
UNC path is necessary to connect to network share.
It could be the chance that 'dir' may failed to find UNC path. 13

14. Method 2: Unnamed SAS Pipes
Pipes Under UNC Path
How to deal with the situation that dir failed?
Dos command "subst" - Associates a path with a driver letter.
Steps to establish a virtual driver that dir can find.
Set SAS options 'noxwait'.
Using X statement and the dos command "subst" to assign the target path to a virtual driver.
With virtual driver set up, pipes could work again. 14

15. Method 2: Unnamed SAS Pipes
Pipes Under UNC Path
Example (assign a UNC path "\\global\project\data" to virtual driver)
option noxwait;
X 'subst n: \\global\project\data';
Example (results) 15

16. Discussion & Conclusion
Applying in More Fields
Example: To compare the latest 2 batches of extracted data.
filename indata pipe 'dir “C:\extracted" /b';
data fnam;
infile indata truncover;
input fnam $200.;
fnam2=lag(fnam);
call symput('last', strip(fnam2));
call symput('current', strip(fnam));
run;
File driven approaches can be more flexible.

17. Discussion & Conclusion
Now we could:
Importing external data. (CSV XLS ...)
Combining outputs. (RTF LST ... )
Coordinating with other techniques to function more.
With methods of:
SAS 'D-' functions.
SAS pipes.
In addition, with SAS pipes, we gain
More efficiency.
Less heavy code.
More flexibility. 17

18. Q&A Thanks 18