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Programming Tips

Strengthen your programming skills with tips and techniques from the experts

Programming Tips

Peter Styliadis

Peter StyliadisDecember 16, 2022 0

CAS-Action! Grouping Frequency Tables - Part 3

Welcome back to my SAS Users blog series CAS Action! - a series on fundamentals. In my previous part 1 and part 2 posts I reviewed how to use the simple.freq CAS action to generate frequency distributions for one or more columns and how to save the results. In this post I

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Programming Tips

Ron CodyDecember 14, 2022 0

Using SAS to score a test

If you have ever needed to score a multiple-choice test, this blog is for you. Even if you are not planning to score a test, the techniques used in this example are useful for many other programming tasks. The example I am going to present assumes the answer key and

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Analytics | Learn SAS | Programming Tips

ARH(1) covariance structure

Rick WicklinDecember 14, 2022 0

Construct heterogeneous structured covariance matrices in SAS

A previous article describes how to use SAS IML software to construct common covariance structures that are encountered in mixed models. Each covariance matrix has several parameters, and you want to construct a matrix for any choice of the parameters. After you have constructed the covariance matrix, you can use

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Programming Tips

Peter Styliadis

Peter StyliadisDecember 12, 2022 0

CAS-Action! Saving Frequency Tables - Part 2

Welcome back to my SAS Users blog series CAS Action! - a series on fundamentals. In my previous post CAS-Action! Simple Frequency Tables - Part 1, I reviewed how to use the simple.freq CAS action to generate frequency distributions for one or more columns using the distributed CAS server. In this post

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Learn SAS | Programming Tips

Rick WicklinDecember 12, 2022 0

Properties of the Hadamard product

I always emphasize efficiency in statistical programming. I have previously written about why you should never multiply with a large diagonal matrix in the SAS IML language. The reason is that it is more efficient to use elementwise multiplication than matrix multiplication. Specifically, if d is a column vector, then

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Analytics | Programming Tips

Peter Styliadis

Peter StyliadisDecember 7, 2022 0

CAS-Action! Simple Frequency Tables - Part 1

Welcome back to my SAS Users blog series CAS Action! - a series on fundamentals. If you'd like to start by learning more about the distributed CAS server and CAS actions, please see CAS Actions and Action Sets - a brief intro. Otherwise, let's learn how to generate frequency distributions for one

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinDecember 7, 2022 0

Art in SAS: Christmas wrapping paper

For Christmas 2021, I wrote an article about palettes of Christmas colors, chiefly shades of red, green, silver, and gold. One of my readers joked that she would like to use my custom palette to design her own Christmas wrapping paper! I remembered her jest when I saw some artwork

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Analytics | Programming Tips

Peter Styliadis

Peter StyliadisDecember 1, 2022 0

CAS-Action! Rename Columns in a CAS Table

Welcome back to my SAS Users blog series CAS Action! - a series on fundamentals. If you'd like to start by learning more about the distributed CAS server and CAS actions, please see CAS Actions and Action Sets - a brief intro. Otherwise, let's learn how to rename columns in CAS tables.

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Learn SAS | Programming Tips

Rick WicklinNovember 30, 2022 0

Ladders: A probabilistic card trick

A probabilistic card trick is a trick that succeeds with high probability and does not require any skill from the person performing the trick. I have seen a certain trick mentioned several times on social media. I call it "ladders" or the "ladders game" because it reminds me of the

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Learn SAS | Programming Tips

Rick WicklinNovember 28, 2022 0

Simulate poker hands in SAS

A SAS programmer was trying to simulate poker hands. He was having difficulty because the sampling scheme for simulating card games requires that you sample without replacement for each hand. In statistics, this is called "simple random sampling." If done properly, it is straightforward to simulate poker hands in SAS.

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Analytics | Programming Tips

Rick WicklinNovember 21, 2022 0

The area under a piecewise linear curve

Recently, I needed to know "how much" of a piecewise linear curve is below the X axis. The coordinates of the curve were given as a set of ordered pairs (x1,y1), (x2,y2), ..., (xn, yn). The question is vague, so the first step is to define the question better. Should

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Analytics | Data Visualization | Programming Tips

Rick WicklinNovember 16, 2022 0

Optimal linear profile plots in SAS

A profile plot is a way to display multivariate values for many subjects. The optimal linear profile plot was introduced by John Hartigan in his book Clustering Algorithms (1975). In Michael Friendly's book (SAS System for Statistical Graphics, 1991), Friendly shows how to construct an optimal linear profile by using

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinNovember 14, 2022 0

Profile plots in SAS

A profile plot is a compact way to visualize many variables for a set of subjects. It enables you to investigate which subjects are similar to or different from other subjects. Visually, a profile plot can take many forms. This article shows several profile plots: a line plot of the

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Programming Tips | SAS Administrators

Leonid BatkhanNovember 8, 2022 0

SAS administrator tip: How to identify and prevent duplicate librefs in SAS metadata

In this SAS administration tutorial Leonid Batkhan presents various SAS programming solutions on how to identify and prevent duplicate LIBREFs in SAS 9 metadata.

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Analytics | Data Visualization | Learn SAS | Programming Tips

Rick WicklinNovember 7, 2022 0

The area of the convex hull of random points

I recently blogged about how to compute the area of the convex hull of a set of planar points. This article discusses the expected value of the area of the convex hull for n random uniform points in the unit square. The article introduces an exact formula (due to Buchta,

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Programming Tips | Work & Life at SAS

Joseph CastleNovember 4, 2022 0

Building an open source software community

Joseph Castle offers some important considerations that will help you when building and working in an OSS community.

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Analytics | Learn SAS | Programming Tips

Rick WicklinNovember 2, 2022 0

The area and perimeter of a convex hull

The area of a convex hull enables you to estimate the area of a compact region from a set of discrete observations. For example, a biologist might have multiple sightings of a wolf pack and want to use the convex hull to estimate the area of the wolves' territory. A

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Programming Tips

Dr. Christian FG Schendera

Dr. Christian FG SchenderaNovember 1, 2022 0

Unexpected results from missing values with PROC SQL

SAS SQL handles missing values differently than the ANSI standard for SQL. PROC SQL follows the SAS convention for handling missing values: numerical missing values are always interpreted as less or smaller than all nonmissing values. My first blog showed that missing values can be troublemakers in non-grouped descriptive statistics.

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Learn SAS | Programming Tips

Rick WicklinOctober 31, 2022 0

A trick to combine and split strings

Every year, I write a special article for Halloween in which I show a SAS programming TRICK that is a real TREAT! This year, the trick is to concatenate two strings into a single string in a way that guarantees you can always recover the original strings. I learned this

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Analytics | Learn SAS | Programming Tips

Rick WicklinOctober 24, 2022 0

Implement binary logistic regression from first principles

I recently gave a presentation about the SAS/IML matrix language in which I emphasized that a matrix language enables you to write complex analyses by using only a few lines of code. In the presentation, I used least squares regression as an example. One participant asked how many additional lines

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Programming Tips

Chevell ParkerOctober 21, 2022 0

Formatting your Microsoft Excel output using ODS Excel

SAS' Chevell Parker walks you through eight formatting scenarios that can occur when using ODS Excel and how to address them using formatting and formatting values after export.

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Analytics | Learn SAS | Programming Tips

Rick WicklinOctober 19, 2022 0

On solving rank-deficient systems of equations in SAS

Recently, I needed to write a program that can provide a solution to a regression-type problem, even when the data are degenerate. Mathematically, the problem is an overdetermined linear system of equations X*b = y, where X is an n x p design matrix and y is an n x 1 vector. For most

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Learn SAS | Programming Tips

Leonid BatkhanOctober 18, 2022 0

Adaptive SAS programming for the Software Development Life Cycle

Leonid Batkhan reveals programming technique to build adaptive SAS programs to facilitate transition between various environments for a smoother SDLC.

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Data Visualization | Programming Tips

Cindy WangOctober 14, 2022 0

Export a Visual Analytics report using REST APIs

In my previous blog Programmatically export a Visual Analytics report to PDF - SAS Users, I use the SAS Visual Analytics SDK to export a report to PDF, which is quite simple if we have basic knowledge with JavaScript programming. It works for both the latest version of SAS Viya

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Programming Tips

Peter Styliadis

Peter StyliadisOctober 13, 2022 0

Getting started with Python integration to SAS® Viya® - Part 11 - Rename Columns

Welcome to the continuation of 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 summarize columns. Now it's time to focus on how to rename columns in CAS tables. Load and explore data

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Learn SAS | Programming Tips

Rick WicklinOctober 10, 2022 0

The expected volume of a random tetrahedron in a cube

One of the benefits of social media is the opportunity to learn new things. Recently, I saw a post on Twitter that intrigued me. The tweet said that the expected volume of a random tetrahedron in the unit cube (in 3-D) is E[Volume] = 0.0138427757.... This number seems surprisingly small!

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Programming Tips

Peter Styliadis

Peter StyliadisOctober 6, 2022 0

Getting Started with Python Integration to SAS® Viya® - Part 10 - Group and Aggregate CAS Tables

Group and aggregate CAS tables Welcome to the continuation of 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 summarize columns. Now it's time to focus on how to group and aggregate CAS

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Learn SAS | Programming Tips

Rick WicklinOctober 5, 2022 0

Checksums and data integrity in SAS programs

Have you ever typed your credit card into an online order form and been told that you entered the wrong number? Perhaps you wondered, "How do they know that the numbers I typed do not make a valid credit card number?" The answer is that credit card numbers and other

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Programming Tips

Suzanne MorgenOctober 3, 2022 0

Meet our SAS Press Author of the Month -- Jane Eslinger

We publish a lot of books by SAS experts at SAS Press, but how does someone become an expert in the first place? Becoming certified is one step, but who develops the certifications in the first place? Those are the true experts. They have to have a deep understanding of

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Analytics | Learn SAS | Programming Tips

Rick WicklinOctober 3, 2022 0

Compute moments of probability distributions in SAS

A previous article discusses the definitions of three kinds of moments for a continuous probability distribution: raw moments, central moments, and standardized moments. These are defined in terms of integrals over the support of the distribution. Moments are connected to the familiar shape features of a distribution: the mean, variance,

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