Feng Jiang

Async Task with Progress Reporting and Cancellation

Sun, 06 Dec 2020 00:00:00 +0000

While building a WinForms application, I needed to run a calculation that could take a long time. I wanted the main form to stay responsive while a separate dialog showed progress and gave the user a cancel button.

Progress reporting and cancellation are common questions, but many examples show only isolated snippets. This sample puts the pieces together in one small application, using IProgress<T> for progress updates and CancellationToken for cancellation.

Better Organization of R Markdown Outputs

Thu, 19 Nov 2020 00:00:00 +0000

By default, the Knit button renders R Markdown output into the same folder as the source .Rmd file. The R Markdown Cookbook shows how to change that behavior by defining a custom knit function in the YAML front matter.

Using that technique, you can keep generated notebooks and reports out of the folders that hold your source code.

Suppose your project is organized with the following folder structure:

Project\
 + Documents\
 + R Code\
   + Project.Rproj
   + Include.R
   + 1 Load\
     + 11 Load Student Data.Rmd
     + 11 Load Student Data.nb.html
     + 12 Load School Data.Rmd
     + 12 Load School Data.nb.html
   + 2 Calculation\
   + 3 Check\
 + R Data\
 + Raw Data\
 + Results\

Because R Notebook and R Markdown outputs are saved next to the source files by default, the R code folder can become cluttered quickly. Reusing the same output filename also makes it harder to keep versions. A cleaner structure is to save dated outputs in a separate folder, like this:

Export R Data to SAS

Wed, 18 Nov 2020 00:00:00 +0000

The Problem

Importing SAS data into R is straightforward: the haven package provides read_sas(), which reads *.sas7bdat files into an R data frame. Going the other direction is harder. In my experience, *.sas7bdat files created by haven::write_sas() were not reliably readable in SAS.

At first, it seems that a shared data format should solve the problem. R can export CSV files, and SAS can import them. Wouldn’t that be enough?

Use CSVY Format for Data Storage

Wed, 18 Nov 2020 00:00:00 +0000

I have used fread() and fwrite() from the data.table package for years. Recently, I noticed that a change introduced in version 1.11.0 broke some old code. The change was:

Numeric data that has been quoted is now detected and read as numeric.

Quoted numbers used to be read as character values. Now, data.table can read quoted numbers as numeric values even when they are quoted.

The old code still runs, but the data no longer arrives in the expected form. For example, an ID column with values such as “0001, 0002, 0003, …” may be read as “1, 2, 3, …”. That does not trigger an immediate error. The failure appears later, when downstream code tries to treat the ID column as character data.

Run a SAS Script from R

Mon, 16 Nov 2020 00:00:00 +0000

Unlike SAS, which can host an R session after the right setup, R cannot host a SAS session directly.

R can, however, call operating-system commands with system(). SAS can also run a .sas script from the command line. Connecting these two sides together, an R script can launch SAS and run a .sas script file.

The command-line syntax for running a SAS script is:

"C:\Program Files\SASHome\SASFoundation\9.4\sas.exe" -SYSIN "path\to\example.sas"

In R, call that command through system():

Run R Code in SAS

Sun, 15 Nov 2020 00:00:00 +0000

SAS can run R code inside a SAS program, but only after R support is enabled. The setup has two parts: turn on R integration in SAS, and tell SAS where R is installed.

Set Up R Support in SAS

First, launch SAS with R support enabled. You can do this in either of two ways:

Add -RLANG to the SAS command line.
Add -RLANG to the end of the SAS configuration file, sasv9.cfg.

Second, tell SAS where to find R. You can do this in either of two ways:

Education and Experience

Mon, 01 Jan 0001 00:00:00 +0000

Education

2012

Ph.D., Curriculum and Instruction (Science Education)

University of Arkansas, Fayetteville, AR.

2006

M.Ed., Physics Education

Capital Normal University, Beijing, China.

1998

B.S., Physics Education

Nanjing Normal University, Nanjing, China.

Professional Experience

2025-Present

Director

Office of Innovation for Education, University of Arkansas.

2022-2024

Assistant Director of Research and Planning

Office of Innovation for Education, University of Arkansas.

2016-2022

Research Associate

Office of Innovation for Education, University of Arkansas.

2014-2016

Research Assistant

Office of Innovation for Education, University of Arkansas.

Publications

Mon, 01 Jan 0001 00:00:00 +0000

Lee, O., Llosa, L., Jiang, F., O'Connor, C., & Haas, A. (2016). School resources in teaching science to diverse student groups: An intervention's effect on elementary teachers' perceptions. Journal of Science Teacher Education, 27(7), 769-794.
Llosa, L., Lee, O., Jiang, F., Haas, A., O'Connor, C., Van Booven, C. (2016). Elementary teachers' science knowledge and instructional practices: Impact of an intervention focused on English language learners. Journal of Research in Science Teaching. 53(4), 579-597.
Llosa, L., Lee, O., Jiang, F., Haas, A., O'Connor, C., Van Booven, C., & Kieffer, M. J. (2016). Impact of a large-scale science intervention focused on English language learners. American Educational Research Journal. 53(2), 395-424.
Jiang, F. & McComas, W. F. (2015). The effects of inquiry teaching on student science achievement and attitudes using propensity score analysis of PISA data. International Journal of Science Education. 37(3), 554-576.
Jiang, F. & McComas, W. F. (2014). Analysis of nature of science included in recent popular science writing using text mining techniques. Science & Education. 23(9), 1785-1809.