Strengthen your programming skills with tips and techniques from the experts
SAS' Mark Jordan shows you how to modify data using PROC SQL, PROC DATASETS and SAS macros.
For some reason, SAS programmers like to express their love by writing SAS programs. Since Valentine's Day is next week, I thought I would add another SAS graphic to the collection of ways to use SAS to express your love. Last week, I showed how to use vector operation and
I recently showed how to find the intersection between a line and a circle. While working on the problem, I was reminded of a fun mathematical game. Suppose you make a billiard table in the shape of a circle or an ellipse. What is the path for a ball at
Recently, I needed to implement a line search algorithm in SAS. The line search is illustrated by the figure at the right. You start with a point, p, in d-dimensional space and a direction vector, v. (In the figure, d=2, but in general d > 1.) The goal is to
When we moved out to the country with our two dogs, our oldest dog Todd suddenly decided he liked to howl…. And he would do so every time we left the house. Maybe it was the country air? Maybe it was a time-lapse gene? Maybe he just wanted to learn
Recently, a SAS programmer commented about one of my blog posts. He said that he had found an alternative answer on another website. Whereas my answer was formulated in terms of the normal cumulative distribution function (CDF), the other answer used the ERF function. This article shows the relationship between
This article introduces how to solve the pirate game with a recursive solving algorithm in SAS, and how to analyze and visualize the law behind the complex logic of the pirate game. If you join in a pirate game next time, you can know your destiny ahead of time to reap the benefits and avoid getting killed.
Many SAS programmers use macros. I have seen students in my SAS classes use several methods to activate their macros. One way is to load the macro in the Display manager or editor in SAS OnDemand for Academics and submit it. Another technique is to use the statement %Include macro-name.
Sometimes it is useful to know the extreme values in data. You might need to know the Top 5 or the Top 10 smallest data values. Or, the Top 5 or Top 10 largest data values. There are many ways to do this in SAS, but this article shows examples
How can you estimate percentiles in SAS Viya? This article shows how to call the percentile action from PROC CAS to estimate percentiles of variables in a CAS data table. Percentiles and quantiles are essentially the same (the pth quantile is the 100*pth percentile for p in [0, 1]), so
Here's a fun problem to think about: Suppose that you have two different valid ways to test a statistical hypothesis. For a given sample, will both tests reject or fail to reject the hypothesis? Or might one test reject it whereas the other does not? The answer is that two
I use macros extensively in my SAS programs, and over the years have accumulated a few that I find quite useful. The integration of GIT and SAS Studio has made it easy to build a re-usable macro library, so I've put some of the more polished macros I've written in
Several probability distributions model the outcomes of various trials when the probabilities of certain events are given. For some distributions, the definitions make sense even when a probability is 0. For other distributions, the definitions do not make sense unless all probabilities are strictly positive. This article examines how zero
Leonid Batkhan describes and discusses pros and cons of 3 different algorithms and SAS code implementations to calculate length of overlap of date/time intervals and integer intervals in general.
Some colors have names, such as "Red," "Magenta," and "Dark Olive Green." But the most common way to specify a color is to use a hexadecimal value such as CX556B2F. It is not obvious that "Dark Olive Green" and CX556B2F represent the same color, but they do! I like to
Last year, I wrote a blog demonstrating how to use the %Auto_Outliers macro to automatically identify possible data errors. This blog demonstrates a different approach—one that is useful for variables for which you can identify reasonable ranges of values for each variable. For example, you would not expect resting heart
On this blog, I write about a diverse set of topics that are relevant to statistical programming and data visualization. In a previous article, I presented some of the most popular blog posts from 2021. The most popular articles often deal with elementary or familiar topics that are useful to
Welcome to the sixth installment in my series Getting Started with Python Integration to SAS Viya. In previous posts, I discussed how to connect to the CAS server, how to execute CAS actions, and how to work with the results. Now it's time to generate simple descriptive statistics of a CAS table. Let's begin
You can use the Cholesky decomposition of a covariance matrix to simulate data from a correlated multivariate normal distribution. This method is encapsulated in the RANDNORMAL function in SAS/IML software, but you can also perform the computations manually by calling the ROOT function to get the Cholesky root and then
Last year, I wrote almost 100 posts for The DO Loop blog. My most popular articles were about data visualization, statistics and data analysis, and simulation and bootstrapping. If you missed any of these gems when they were first published, here are some of the most popular articles from 2021:
Let's take a look at the design and implementation of SAS functions in financial calculations. We'll do this through examples calculating and analyzing the monthly payment, interest, and principal for CPM/CAM mortgages.
Because it is near the end of the year, I thought a blog about "Summarizing" data might be in order. For these examples, I am going to use a simulated data set called Drug_Study, containing some categorical and numerical variables. For those interested readers, the SAS code that I used
CAS libraries enable you to access your CAS data. By defining the librefs for those caslibs in SAS Studio, you can have more interactive access to the CAS data.
This post is written in the hopes of easing the SAS Viya deployment process for novices like me. Firstly, deploying SAS Viya, like most enterprise software packages, isn't a skill we're innately born with. We're going to need a little help, some good documentation, and time to absorb the intricoes
While discussing how to compute convex hulls in SAS with a colleague, we wondered how the size of the convex hull compares to the size of the sample. For most distributions of points, I claimed that the size of the convex hull is much less than the size of the
When we wrote the sixth edition of The Little SAS Book: A Primer, one of our goals was to write it for all SAS programmers regardless of which interface they use for coding: SAS Studio, SAS Enterprise Guide, the SAS windowing environment, or batch. This is harder than it sounds.
A scatter plot is my go-to graph! It's what I often start with to get a feel for the data ... and I often end up using just a scatter plot. But some scatter plots are better than others ... In this blog post, I create a scatter plot of
When SAS 9 programmers transition to SAS Viya, there are inevitably questions about how new concepts in Cloud Analytic Services (CAS) relate to similar concepts in SAS. This article discusses the question, "What is the difference between a libref and a caslib?" Both are used to access data, but they
In a previous article, I showed how to use theCVEXHULL function in SAS/IML to compute the convex hull of a finite set of planar points. The convex hull is a convex polygon, which is defined by its vertices. To visualize the polygon, you need to know the vertices in sequential
This blog is a continuation of a previous blog that discussed creating simulated data sets. If you have not seen it, you might want to review it, especially if you are not familiar with the RAND function. The program that I'm going to show you simulates a drug study with
