The DO Loop

Programming Tips

Strengthen your programming skills with tips and techniques from the experts

Rick WicklinNovember 8, 2017 0

A SAS programmer wanted to display a table in which the rows have different formats. An example is shown below. The programmer wanted columns that represent statistics and rows that represent variables. She wanted to display formats (such as DOLLAR) for some variables—but only for certain statistics. For example, the

English

Programming Tips

Rick WicklinNovember 6, 2017 0

What is a factoid in SAS?

Have you ever seen the "Fit Summary" table from PROC LOESS, as shown to the right? Or maybe you've seen the "Model Information" table that is displayed by some SAS analytical procedures? These tables provide brief interesting facts about a statistical procedure, hence they are called factoids. In SAS, a

English

Programming Tips

Rick WicklinNovember 1, 2017 0

Evaluate a function by using the function name in SAS/IML

A SAS/IML programmer asked whether you can pass the name of a function as an argument to a SAS/IML module and have the module call the function that is passed in. The answer is "yes." The basic idea is to create a string that represents the function call and then

English

Data Visualization | Programming Tips

Rick WicklinOctober 30, 2017 1

A SAS programming technique to modify ODS templates

This article demonstrates a SAS programming technique that I call Kuhfeld's template modification technique. The technique enables you to dynamically modify an ODS template and immediately call the modified template to produce a new graph or table. By following the five steps in this article, you can implement the technique

English

Programming Tips

Rick WicklinOctober 11, 2017 0

Simulate correlations by using the Wishart distribution

The article "Fisher's transformation of the correlation coefficient" featured a Monte Carlo simulation that generated sample correlations from bivariate normal data. The simulation used three steps: Simulate B samples of size N from a bivariate normal distribution with correlation ρ. Use PROC CORR to compute the sample correlation matrix for

English

Programming Tips

Heat map of correlations between variables

Rick WicklinOctober 9, 2017 1

Order correlations by magnitude

Correlations between variables are typically displayed in a matrix. Because the correlation matrix is determined by the order of the variables, it is difficult to find the largest and smallest correlations, which is why analysts sometimes use colors to visualize the correlation matrix. Another visualization option is the pairwise correlation

English

Learn SAS | Programming Tips

Results of a data-driven simulation in which parameters are stored in a file and processed by a SAS program

Rick WicklinSeptember 27, 2017 5

Data-driven simulation

In a large simulation study, it can be convenient to have a "control file" that contains the parameters for the study. My recent article about how to simulate multivariate normal clusters demonstrates a simple example of this technique. The simulation in that article uses an input data set that contains

Analytics | Programming Tips

Rick WicklinSeptember 25, 2017 6

Simulate multivariate normal data in SAS by using PROC SIMNORMAL

My article about Fisher's transformation of the Pearson correlation contained a simulation. The simulation uses the RANDNORMAL function in SAS/IML software to simulate multivariate normal data. If you are a SAS programmer who does not have access to SAS/IML software, you can use the SIMNORMAL procedure in SAS/STAT software to

English

Advanced Analytics | Learn SAS | Programming Tips

Simulate clustered data from a Gaussian mixture distribution

Rick WicklinSeptember 13, 2017 7

Simulate multivariate clusters in SAS

This article shows how to simulate data from a mixture of multivariate normal distributions, which is also called a Gaussian mixture. You can use this simulation to generate clustered data. The adjacent graph shows three clusters, each simulated from a four-dimensional normal distribution. Each cluster has its own within-cluster covariance,

English

Analytics | Programming Tips

Rick WicklinSeptember 11, 2017 1

Symbolic derivatives in SAS

Did you know that you can get SAS to compute symbolic (analytical) derivatives of simple functions, including applying the product rule, quotient rule, and chain rule? SAS can form the symbolic derivatives of single-variable functions and partial derivatives of multivariable functions. Furthermore, the derivatives are output in a form that

English

Blogs

Blogs

Programming Tips