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Strengthen your programming skills with tips and techniques from the experts

Analytics | Learn SAS | Programming Tips

Rick WicklinJuly 19, 2023 0

On the computation of the Wilcoxon signed rank statistic

Wilcoxon's signed rank test is a popular nonparametric alternative to a paired t test. In a paired t test, you analyze measurements for subjects before and after some treatment or intervention. You analyze the difference in the measurements for each subject, and test whether the mean difference is significantly different

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Learn SAS | Programming Tips

Rick WicklinJuly 10, 2023 0

Simulate from a Markov model

A previous article shows an example of a Markov chain model and computes the probability that the system ends up in a terminal state (called an absorbing state). As explained previously, you can often compute exact probabilities for questions about Markov chains. Nevertheless, it can be useful to know how

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Learn SAS | Programming Tips

Rick WicklinJuly 5, 2023 0

The probability of reaching a terminal state in a Markov chain

A previous article shows how to model the probabilities in a discrete-time Markov chain by using a Markov transition matrix. A Markov chain is a discrete-time stochastic process for which the current state of the system determines the probability of the next state. In this process, the probabilities for transitioning

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Analytics | Learn SAS | Programming Tips

Rick WicklinJune 28, 2023 0

Compute the geometric median in SAS

Given a set of N points in k-dimensional space, can you find the location that minimizes the sum of the distances to the points? The location that minimizes the distances is called the geometric median of the points. For univariate data, the "points" are merely a set of numbers $${p_1,

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Learn SAS | Programming Tips

Rick WicklinJune 19, 2023 0

Use built-in ODS templates to display SAS tables

Part of the power of the SAS ODS system is the ability to visualize data by using ODS templates. An ODS template describes how to render data as a table or as a graph. A lot of papers and documentation have been written about how to define a custom template

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Learn SAS | Programming Tips

Rick WicklinJune 14, 2023 0

Eigenvalues of a tridiagonal Toeplitz matrix

While writing an article about Toeplitz matrices, I saw an interesting fact about the eigenvalues of tridiagonal Toeplitz matrices on Nick Higham's blog. Recall that a Toeplitz matrix is a banded matrix that is constant along each diagonal. A tridiagonal Toeplitz matrix is zero except for the main diagonal, the

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Learn SAS | Programming Tips

Rick WicklinJune 12, 2023 0

How to construct an unsymmetric Toeplitz matrix

A Toeplitz matrix is a banded matrix. You can construct it by specifying the parameters that are constant along each diagonal, including sub- and super-diagonals. For a square N x N matrix, there is one main diagonal, N-1 sub-diagonals, and N-1 super-diagonals, for a total of 2N-1 parameters. In statistics and applied

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Analytics | Learn SAS | Programming Tips

Noah HanJune 7, 2023 0

SoDA로 데이터 과학 시작하기

SoDA를 이용해 쉽게 배우는 데이터 과학 #1 SoDA(SAS OnDemand for Academics)는 SAS가 무료로 제공하는 교육용 데이터 분석 소프트웨어 프로그램입니다. 앞으로 4회에 걸쳐 'SoDA 를 이용해 쉽게 배우는 데이터 과학'을 자세히 소개해 드리도록 하겠습니다. SoDA란? SoDA (SAS OnDemand for Academics; SoDA)는 데이터 과학을 처음 배우는 입문자들에게 SAS를 무료로 배울 수 있도록

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Programming Tips

Leonid BatkhanMay 30, 2023 0

Embedding any code anywhere into SAS programs

SAS expert Leonid Batkhan presents the %embed macro function as a way to embed both “foreign” and SAS native code from a file into a SAS program, preventing clutter in your code.

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Programming Tips

Peter Styliadis

Peter StyliadisMay 30, 2023 0

Getting Started with Python Integration to SAS® Viya® - Part 19 - Load Multiple CSV Files

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In this post I'll discuss how to load multiple CSV files into memory as a single table using the loadTable action. Load and prepare data on the CAS server To start, we need to create multiple

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Learn SAS | Programming Tips

Rick WicklinMay 22, 2023 0

Rank character variables in SAS

SAS supports many ways to compute the rank of a numeric variable and to handle tied values. However, sometimes I need to rank the values in a character categorical variable. For example, the values {"Male", "Female", "Male"} have ranks {2, 1, 2} because, in alphabetical order, "Female" is the first-ranked

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Advanced Analytics | Data Visualization | Programming Tips

Rick WicklinMay 17, 2023 0

Compute the silhouette statistic in SAS

A previous article defines the silhouette statistic (Rousseeuw, 1987) and shows how to use it to identify observations in a cluster analysis that are potentially misclassified. The article provides many graphs, including the silhouette plot, which is a bar chart or histogram that displays the distribution of the silhouette statistic

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Learn SAS | Programming Tips

Rick WicklinMay 8, 2023 0

An interview question for SAS programmers

Recently, I learned about an elementary programming assignment called the FizzBuzz program. Some companies use this assignment for the first round of interviews with potential programmers. A competent programmer can write FizzBuzz in 5-10 minutes, which leaves plenty of time to discuss other topics. If an applicant can't complete the

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Programming Tips

George BeeversMay 4, 2023 0

Debunking the myth that SAS code doesn't work in Viya: One billion lines later and the results are...

The SAS 9 Content Assessment is a collection of applications that are designed to help users understand the various characteristics of their deployment. SAS Content Assessment delivers information that is critical to helping you to upgrade to the latest version of SAS (Viya).

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Analytics | Programming Tips

Rick WicklinMay 3, 2023 0

The exponential of a matrix

In SAS, you can approximate the exponential of a matrix by using the EXPMATRIX function in SAS IML software. This article discusses the exponential of a matrix: what it is, how to compute it, why it is useful, and why you should think of it as a linear map that

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Learn SAS | Programming Tips

Rick WicklinApril 24, 2023 0

Venn diagrams that illustrate relationships between sets

A previous article discusses how to compute the union, intersection, and other subsets of a pair of sets. In that article, I displayed a simple Venn diagram (reproduced to the right) that illustrates the intersection and difference between two sets. The diagram uses a red disk for one set, a

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Learn SAS | Programming Tips

Lee Ann DietzApril 21, 2023 0

Public Health Transformation: Ways to use SAS Viya

We demonstrate a few common and essential public health functions using SAS Viya. Our goal is to show the art of the possible within the realm of accessibility.

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Programming Tips

Peter Styliadis

Peter StyliadisApril 19, 2023 0

Getting Started with Python Integration to SAS® Viya® - Part 18 - Update rows in a table

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In this post I'll discuss how to update rows in a distributed CAS table. Load and prepare data in the CAS server I created a script to load and prepare data in the CAS server. This

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Learn SAS | Programming Tips

Rick WicklinApril 19, 2023 0

The joy of sets

The fundamental operations on sets are union, intersection, and set difference, all of which are supported directly in the SAS IML language. While studying another programming language, I noticed that the language supports an additional operation, namely the symmetric difference between two sets. The language also supports query functions to

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Programming Tips

Kathryn McLawhornApril 18, 2023 0

Adding dynamic counts in headings in the PROC REPORT output

SAS' Kathryn McLawhorn reveals an elegant option to introduce dynamic header data using DATA step logic and the FORMAT procedure.

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Analytics | Learn SAS | Programming Tips

Rick WicklinApril 17, 2023 0

Should you use the Wald confidence interval for a binomial proportion?

The "Teacher’s Corner" of The American Statistician enables statisticians to discuss topics that are relevant to teaching and learning statistics. Sometimes, the articles have practical relevance, too. Andersson (2023) "The Wald Confidence Interval for a Binomial p as an Illuminating 'Bad' Example," is intended for professors and masters-level students in

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Programming Tips

Peter Styliadis

Peter StyliadisApril 6, 2023 0

Getting Started with Python Integration to SAS® Viya® - Part 17 - Saving CAS tables

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In this post I'll discuss saving CAS tables to a caslib's data source as a file. This is similar to saving pandas DataFrames using to_ methods. Load and preview the CAS table First, I imported the

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Data Management | Programming Tips

Melodie RushApril 5, 2023 0

Getting Started with Python Integration to SAS Viya for Predictive Modeling - Working with Dates

In part 1 of this series, we examined our data before building any models. Among the discoveries was a column that seemed to contain a SAS date value. Here, we will discuss what exactly is meant by a 'SAS date', how to format it correctly, and how to create a

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Programming Tips

Peter Styliadis

Peter StyliadisApril 3, 2023 0

Getting Started with Python Integration to SAS® Viya® - Part 16 - Execute SQL

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In this post I'll discuss how to execute SQL with the Python SWAT package in the distributed CAS server. Prepare and load data to the CAS server I created a Python function named createDemoData to prepare

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Learn SAS | Programming Tips

Rick WicklinMarch 29, 2023 0

Using SAS to solve an introductory programming assignment

I recently discussed introductory programming with a colleague who teaches Python at a university. He told me about the following introductory programming assignment: Let N be an integer parameter in the range [1, 9]. For each value of N, find all pairs of one-digit positive integers d1 and d2 that

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Analytics | Learn SAS | Programming Tips

Rick WicklinMarch 22, 2023 0

Partial correlation: controlling for confounding variables

A data analyst wanted to estimate the correlation between two variables, but he was concerned about the influence of a confounding variable that is correlated with them. The correlation might affect the apparent relationship between main two variables in the study. A common confounding variable is age because young people

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Programming Tips

Peter Styliadis

Peter StyliadisMarch 21, 2023 0

Getting Started with Python Integration to SAS® Viya® - Part 15 - Count Missing Values in a CAS Table

Welcome to the continuation of my series Getting Started with Python Integration to SAS Viya. In this post I'll discuss how to count missing values in a CAS table using the Python SWAT package. Load and prepare data First, I connect my Python client to the distributed CAS server and named

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Data Management | Programming Tips

Melodie RushMarch 20, 2023 0

Getting Started with Python Integration to SAS Viya for Predictive Modeling - Index

Welcome to my series on getting started with Python integration to SAS Viya for predictive modeling. Exploring Data - Learn how to explore the data before fitting a model Working with Dates - Learn how to format a SAS Date and calculate a new column Imputing Missing Values - Learn

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Data Management | Programming Tips

Melodie RushMarch 20, 2023 0

Getting Started with Python Integration to SAS Viya for Predictive Modeling - Exploring Data

Welcome to the first post in my series Getting Started with Python Integration to SAS Viya for Predictive Modeling. I'm going to dive right into the content assuming you have minimal knowledge on SAS Cloud Analytic Services (CAS), CAS Actions and Python. For some background on these subjects, refer to

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Learn SAS | Programming Tips

Rick WicklinMarch 20, 2023 0

Estimate a Markov transition matrix from historical data

In a previous article about Markov transition matrices, I mentioned that you can estimate a Markov transition matrix by using historical data that are collected over a certain length of time. A SAS programmer asked how you can estimate a transition matrix in SAS. The answer is that you can

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