Ten tips for learning the SAS/IML language

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A SAS customer wrote, "Now that I have access to PROC IML through the free SAS University Edition, what is the best way for me to learn to program in the SAS/IML language? How do I get started with PROC IML?"

That is an excellent question, and I'm happy to offer some suggestions. The following ideas are ordered according to your level of experience with SAS/IML programming. The first few resources will help beginners get started with PROC IML. The last few suggestions will help intermediate-level programmers develop and improve their SAS/IML programming skills.

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  1. Get the SAS/IML Software. If your workplace does not license the SAS/IML product, you can download the free SAS University Edition onto your laptop for learning SAS/IML. Even if SAS/IML software is available at work, you might want to download the University Edition if you plan to learn and practice at night or on weekends.
  2. Work through the "Getting Started" chapter of the book Statistical Programming with SAS/IML Software. The chapter is available as a free excerpt from the book's Web page. Notice that I say "work through," not "read." Run the programs as you read. Change the numbers in the examples. If you want a longer introduction, read my SAS Global Forum paper "Getting Started with the SAS/IML Language" Wicklin (2013).
  3. Work through the first six chapters of the SAS/IML User's Guide. A few years ago I revised this documentation to make it more readable, especially the sections about reading and writing data.
  4. Download the SAS/IML tip sheets. By keeping a tip sheet on your desk, you can easily remind yourself of the syntax for common SAS/IML statements and functions.
  5. Subscribe to The DO Loop blog. Most Mondays I blog about elementary topics that do not require advanced programming skills. I also discuss DATA step programs, statistical graphics, and SAS/STAT procedures. I've written more than 100 blog posts that are tagged as "Getting Started."
  6. Program, program, program. The way to learn any programming language is to start writing programs in that language. When I was a university professor, I used to tell my students "Math is not a spectator sport." Programming is similar: In order to get better at programming, you need to practice programming. Many of the previous tips provided you with pre-written programs that you can modify and extend. The paper "Rediscovering SAS/IML Software: Modern Data Analysis for the Practicing Statistician" includes intermediate-level examples that demonstrate the power of the SAS/IML language.
  7. Use the SAS/IML Support Community. When you start writing programs, you will inevitably have questions. The SAS/IML Support Community is a discussion forum where you can post code and ask for help. As you gain experience, try answering questions posted by others!
  8. Think about efficiency. A difference between a novice programmer and an experienced programmer is that the experienced programmer can write efficient programs. In a matrix-vector language such as SAS/IML, that means vectorizing programs: using matrix operations instead of loops over variables and observations. Many programming tips and techniques in the first four chapters of Statistical Programming with SAS/IML Software deal with efficiency issues. As you gain experience, study the efficiency examples and vectorization examples in my blog.
  9. Use the SAS/IML Studio programming interface. I am more productive when I use SAS/IML Studio than when I use PROC IML in the SAS Windowing environment (display manager) or even in SAS Studio. I like the color-coded program editor and the ability to develop and run multiple SAS/IML programs simultaneously. I like the debugging features and the dynamically linked graphics are often useful for understanding relationships in data.
  10. Use the SAS/IML File Exchange. The SAS/IML File Exchange is a Web site where you can search for useful programs to use, study, or modify. The exchange is a little like those "Leave a penny; take a penny" bowls at cash registers. If you have written a cool program, contribute it so that others can use it. If you need a function that performs a particular analysis, download it from the site. The site launched in mid-2014, so we need contributions from many SAS/IML programmers before the site will become useful. Do you have a program that you can contribute?

Becoming a better SAS/IML programmer does not happen overnight. Merely reading books and blogs will not make you better. However, the ten tips in this article point out resources that you can use to improve your skills. So roll up your sleeves and start programming!

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About Author

Rick Wicklin

Distinguished Researcher in Computational Statistics

Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of PROC IML and SAS/IML Studio. His areas of expertise include computational statistics, simulation, statistical graphics, and modern methods in statistical data analysis. Rick is author of the books Statistical Programming with SAS/IML Software and Simulating Data with SAS.

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