Formatting and Commenting SAS Programs
Comment statements allow you to document your program without
affecting processing. There are two kinds of comments in SAS:
- All text between the delimiters /* and */ are ignored.
/* This is a comment. */
- If a comment is short, it can be put between a * and ;.
* This is another comment;
Although SAS allows for free-formatted code, a good SAS program will
be well-documented and well-organized.
After the (optional) system OPTIONS statement, every SAS program should
begin with a block of comments. This block of comments should include
the name of the program file, the author, the date on which the program
was written, and text that clearly describes the main purpose, input
and output of the program. Example:
/*
Filename: class.sas
Written by: Dave Steven
Date: January 14, 1997
...
*/
Every critical DATA step or PROC step alsoshould be preceded by a
block of comments, emphasized by asterisks, that describes the
primary purpose of the step. The block of comments also should include
any critical information, such as variable names, input and output of
the block of code.
Comments that pertain to a single line of code are useful, for example,
to describe what an expression is calculating, to describe a new variable
and how it is calculated, why a dataset is subsetted on a particular
set of values, and so on. Here's an example of describing a new variable:
temp_f = 1.8 * temp_c + 32; * Convert Celsius to Fahrenheit;
At least one line, preferably two lines, should separate any DATA or
PROC steps within your SAS programs.
Some people find it useful to capitalize DATA, PROC PROCNAME, and RUN.
For example:
DATA cool;
set NewSASv8;
...
RUN;
Indenting code within a DATA step or PROCedure at least 2 spaces has been
known by many to improve readibility.
Please send questions or suggestions about this web page to beatnic@aset.psu.edu
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