External Files

Working with External Files

The primary reason for reading an external file in a SAS job is to create a SAS data set from raw data. This topic is covered in Reading Raw Data.

Writing to External Files

You can write to an external file by using:

a SAS DATA step
the External File Interface (EFI)
the Export Wizard.

When you use a DATA step to write a customized report, you write it to an external file. In its simplest form, a DATA step that writes a report looks like this:

data _null_;
   set budget;
   file 'your-file-name';
   put variables-and-text;
run;

For examples of writing reports with a DATA step, see DATA Step Processing.

If your operating environment supports a graphical user interface, you can use the EFI or the Export Wizard to write to an external file. The EFI is a point-and-click graphical interface that you can use to read and write data that is not in SAS internal format. By using the EFI, you can read data from a SAS data set and write it to an external file, and you can read data from an external file and write it to a SAS data set. See SAS/ACCESS Interface to PC Files: Reference for more information on the EFI.

Note: If the data file you are passing to EFI is password protected, you will be prompted multiple times for your login ID and password. [cautionend]

The Export Wizard guides you through the steps to read data from a SAS data set and write it to an external file. As a wizard, it is a series of windows that present simple choices to guide you through the process. See SAS/ACCESS Interface to PC Files: Reference for more information on the wizard.

Processing External Files

When reading data from or to a file, you can also use a DATA step to:

copy only parts of each record to another file
copy a file and add fields to each record
process multiple files in the same way in a single DATA step
create a subset of a file
update an external file in place
write data to a file that can be read in different computer environments
correct errors in a file at the bit level.

For examples of using a DATA step to process external files, see Reading Raw Data.

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