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Programming Tips

Strengthen your programming skills with tips and techniques from the experts

Programming Tips

Sian RobertsJune 18, 2019 0

Understanding Item Response Theory with SAS

What is Item Response Theory? Item Response Theory (IRT) is a way to analyze responses to tests or questionnaires with the goal of improving measurement accuracy and reliability. A common application is in testing a student’s ability or knowledge. Today, all major psychological and educational tests are built using IRT.

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Data Visualization | Programming Tips

Robert AllisonJune 14, 2019 0

Fine-tuning the date axis in your bar chart

In these modern times, my utility bill has a bar chart so I can see how my current consumption compares to my historical usage. I decided to create my own version of this utility bill bar chart, and make a few improvements along the way. If you're into SGplot bar

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Energy & Utilities

Data Visualization | Programming Tips

Robert AllisonJune 12, 2019 0

Converting from SAS/Graph to ODS Graphics - color control

In this 'Rosetta Graph' example, I demonstrate how to control bar chart colors in Gchart and SGplot. But first, here's a little diversion... some artwork in my office here at SAS. There's a *lot* of artwork hanging around at SAS, but this particular painting wasn't created by the SAS artists

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Advanced Analytics | Programming Tips

Rick WicklinJune 12, 2019 0

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

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Programming Tips | SAS Administrators

Joe FurbeeJune 10, 2019 0

Deploying the Full SAS Viya Stack in Kubernetes

This article is a follow-on to a recent post from Jeff Owens, Getting started with SAS Containers. In that post, Jeff discussed building and running a single container for a SAS Viya runtime/IDE. Today we will go through how to build and run the full SAS Viya stack - visual

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Learn SAS | Programming Tips

Rick WicklinJune 10, 2019 0

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

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Data Visualization | Programming Tips

Robert AllisonJune 6, 2019 0

Converting from Gchart to SGpie - simple pie chart

For my third 'Rosetta Graph' example, I will focus on a simple pie chart. Hopefully this example will show you how to convert your SAS/Graph Proc Gchart pies into almost-identical Proc SGpie pies. And speaking of almost-identical pies, here are two beautiful pies my friend Beth made - which one

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinJune 5, 2019 0

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

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Data Visualization | Programming Tips

Robert AllisonJune 4, 2019 0

Converting from Gchart to SGplot - simple bar chart

You've probably heard of the famous Rosetta Stone. It had the same decree written on it in both ancient Egyptian and Greek, and was an essential key to help modern historians decipher and translate the ancient Egyptian hieroglyphs. To help the 'old timers' (like me) shift from using SAS/Graph to the

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Learn SAS | Programming Tips

Mike ZizziJune 4, 2019 0

SAS or Python? Why not use both? Using Python functions inside SAS programs

Two sayings I’ve heard countless times throughout my life are “Work smarter, not harder,” and “Use the best tool for the job.” If you need to drive a nail, you pick up a hammer, not a wrench or a screwdriver. In the programming world, this could mean using an existing

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Data Visualization | Learn SAS | Programming Tips

Rick WicklinJune 3, 2019 0

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

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Data Visualization | Programming Tips

Robert AllisonMay 29, 2019 0

Converting from Gplot to SGplot - scatter plots

You've probably heard of the famous Rosetta Stone. It had the same decree written on it in both ancient Egyptian and Greek, and was an essential key to help modern historians decipher and translate the ancient Egyptian hieroglyphs. To help the 'old timers' (like me) shift from using SAS/Graph to

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Analytics | Programming Tips

Rick WicklinMay 28, 2019 0

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

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Data Visualization | Programming Tips

Robert AllisonMay 21, 2019 0

Analyzing marathon data with a graph

Marathons seem to be popular these days, therefore I decided to dive into some data and find a way to apply analytics. You might find this interesting if you're a fan of marathons - or if you like seeing the details behind cool graphing techniques! Before we get started, here's

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Sports & Entertainment

Analytics | Programming Tips

Rick WicklinMay 20, 2019 0

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

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Data Visualization | Programming Tips

Robert AllisonMay 16, 2019 0

NC tornado animation (1950-2018)

We recently had some severe storms come through North Carolina, which even spawned a tornado in Wake county (the county where I live and work). This got me wondering when and where we've had tornadoes in NC in the past ... and, of course, I had to create a map!

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Programming Tips

Deva KumarMay 16, 2019 0

GraphQL and SAS Viya applications - a good match

In the article Serverless functions and SAS Viya - a good match I discussed using serverless functions to deliver SAS Viya applications. Ignoring all the buzz words, a serverless function boils down to a set of REST APIs. So, if you tried the example you are now a REST API

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Data Visualization | Learn SAS | Programming Tips

PROC SGMAP SCATTER of Movie Locations

Kelly MillsMay 14, 2019 0

Geocoding US Street Addresses and Plotting Them with PROC SGMAP

I met many SAS programmers at the 2019 SAS Global Forum who geocode addresses using ArcGIS. Did you know that street address locations and other things can be found using the SAS GEOCODE procedure? PROC GEOCODE gives you coordinates for address, ZIP codes, ZIP+4 codes and cities. You can even

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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 =

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Data Visualization | Programming Tips

Robert AllisonMay 9, 2019 0

US natural gas graph has 'flipped'!

You might have seen in the news that US exports of natural gas to Europe are up 300%. And we recently crossed the threshold where we export more natural gas than we import. This seems like a momentous occasion, and worthy of a graph! But first, let me make sure

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Energy & Utilities

Programming Tips

Leonid BatkhanMay 8, 2019 0

Dividing by zero with SAS - myths and realities

To those of you who have not read my previous post, Dividing by zero with SAS, it's not too late to go back and make it up. You missed a lot of fun, deep thought and opportunity to solve an unusual SAS coding challenge. For those who have already read

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Analytics | Programming Tips

Rick WicklinMay 8, 2019 0

Discrimination, accuracy, and stability in binary classifiers

At SAS Global Forum 2019, Daymond Ling presented an interesting discussion of binary classifiers in the financial industry. The discussion is motivated by a practical question: If you deploy a predictive model, how can you assess whether the model is no longer working well and needs to be replaced? Daymond

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Analytics | Data Visualization | Programming Tips

Lavanya MandavilliMay 6, 2019 0

Five key security features in the SAS Visual Analytics app

App security is at the top of mind for just about everybody – users, IT folks, business executives. Rightfully so. Mobile apps and the devices on which they reside tend to travel around, without any physical boundaries that encompass the traditional desktop computers. In chatting with folks who are evaluating

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Analytics | Programming Tips

Rick WicklinMay 6, 2019 0

How to simulate data from a generalized linear model

Here's a simulation tip: When you simulate a fixed-effect generalized linear regression model, don't add a random normal error to the linear predictor. Only the response variable should be random. This tip applies to models that apply a link function to a linear predictor, including logistic regression, Poisson regression, and

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Data Visualization | Programming Tips

Robert AllisonApril 30, 2019 0

Mortgage rate graph animation

I always recommend looking at data in several different ways to get a more complete mental picture. And when the data is changing over time, one great way to view it is using an animation. Follow along for some tips & tricks to animate your own data over time. I'll

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Learn SAS | Programming Tips

Rick WicklinApril 29, 2019 0

The normal mixture distribution in SAS

Did you know that SAS provides built-in support for working with probability distributions that are finite mixtures of normal distributions? This article shows examples of using the "NormalMix" distribution in SAS and describes a trick that enables you to easily work with distributions that have many components. As with all

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Programming Tips

William BenjaminApril 25, 2019 0

Making the most of the ODS Excel destination

As a SAS programmer, you are asked to do many things with your data -- reading, writing, calculating, building interfaces, and occasionally sending data outside of SAS. One of the most popular outputs you may be tasked with creating is likely a Microsoft Excel workbook. Have you ever heard, “just

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Data Visualization | Programming Tips

Robert AllisonApril 25, 2019 0

Polar graph remix - using sgplot (no gtl/sgrender!)

A few years ago Sanjay showed how to create a polar graph by creating a gtl template, and then plotting it using Proc SGRender. These days, Proc SGPlot has all the functionality you need to create this graph, therefore I've rewritten the example to just use SGPlot. And while I

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Analytics | Programming Tips

Rick WicklinApril 24, 2019 0

A CUSUM test for autregressive models

The CUSUM test has many incarnations. Different areas of statistics use different assumption and test for different hypotheses. This article presents a brief overview of CUSUM tests and gives an example of using the CUSUM test in PROC AUTOREG for autoregressive models in SAS. A CUSUM test uses the cumulative

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