The DO Loop

Programming Tips

Strengthen your programming skills with tips and techniques from the experts

Rick WicklinJuly 8, 2019 3

How to add an annotation to a mosaic plot in SAS

The mosaic plot is a graphical visualization of a frequency table. In previous articles, I showed how to create a mosaic plot in SAS by using PROC FREQ and how to define a template in the Graph Template Language (GTL) by using the MOSAICPARM statement. This article shows how to

English

Learn SAS | Programming Tips

Rick WicklinJuly 3, 2019 3

Create a custom informat in SAS

An informat helps you read data into a SAS data set. SAS supports more than 100 informats. The most common informats are related to dates and times and make it easy to read an input string such as 28JAN2001 and convert it to a SAS date such as 15003. Yet

English

Analytics | Learn SAS | Programming Tips

Rick WicklinJune 26, 2019 1

Jump-start PROC LOGISTIC by using parameter estimates from PROC HPLOGISTIC

SAS/STAT software contains a number of so-called HP procedures for training and evaluating predictive models. ("HP" stands for "high performance.") A popular HP procedure is HPLOGISTIC, which enables you to fit logistic models on Big Data. A goal of the HP procedures is to fit models quickly. Inferential statistics such

English

Advanced Analytics | Programming Tips

Rick WicklinJune 12, 2019 5

Leave-one-out statistics and a formula to update a matrix inverse

For linear regression models, there is a class of statistics that I call deletion diagnostics or leave-one-out statistics. These observation-wise statistics address the question, "If I delete the i_th observation and refit the model, what happens to the statistics for the model?" For example: The PRESS statistic is similar to

English

Learn SAS | Programming Tips

Rick WicklinJune 10, 2019 15

5 reasons to use PROC FORMAT to recode variables in SAS

Recoding variables can be tedious, but it is often a necessary part of data analysis. Almost every SAS programmer has written a DATA step that uses IF-THEN/ELSE logic or the SELECT-WHEN statements to recode variables. Although creating a new variable is effective, it is also inefficient because you have to

English

Data Visualization | Learn SAS | Programming Tips

Rick WicklinJune 5, 2019 2

Plot a family of curves in SAS

A family of curves is generated by an equation that has one or more parameters. To visualize the family, you might want to display a graph that overlays four of five curves that have different parameter values, as shown to the right. The graph shows members of a family of

English

Data Visualization | Learn SAS | Programming Tips

Rick WicklinJune 3, 2019 4

Graph wide data and long data in SAS

Statistical programmers and analysts often use two kinds of rectangular data sets, popularly known as wide data and long data. Some analytical procedures require that the data be in wide form; others require long form. (The "long format" is sometimes called "narrow" or "tall" data.) Fortunately, the statistical graphics procedures

English

Analytics | Programming Tips

Rick WicklinMay 28, 2019 2

The Theil-Sen robust estimator for simple linear regression

Modern statistical software provides many options for computing robust statistics. For example, SAS can compute robust univariate statistics by using PROC UNIVARIATE, robust linear regression by using PROC ROBUSTREG, and robust multivariate statistics such as robust principal component analysis. Much of the research on robust regression was conducted in the

English

Analytics | Programming Tips

Rick WicklinMay 20, 2019 4

Critical values of the Kolmogorov-Smirnov test

Recently I wrote about how to compute the Kolmogorov D statistic, which is used to determine whether a sample has a particular distribution. One of the beautiful facts about modern computational statistics is that if you can compute a statistic, you can use simulation to estimate the sampling distribution of

English

Learn SAS | Programming Tips

Rick WicklinMay 13, 2019 0

Write to a SAS data set from inside a SAS/IML loop

In SAS/IML programs, a common task is to write values in a matrix to a SAS data set. For some programs, the values you want to write are in a matrix and you use the CREATE FROM/APPEND FROM syntax to create the data set, as follows: proc iml; X =

English

Blogs

Blogs

Programming Tips