Blog Archives

Setting the HTML title tag in SAS ODS (the right way)

January 5, 2010
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Setting the HTML title tag in SAS ODS (the right way)

In our department and various places on the Intertubes, SAS programmers set the HTML title tag (which sets the title in web browsers and on search engines) in ODS using the headtext option: ods html headtext="<title>My great report</title>" /* wrong! */ file="foo.html"; This may work in some situations, but it’s ugly and wrong. To see

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R: Memory usage statistics by variable

January 4, 2010
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R: Memory usage statistics by variable

Do you need a way to find out which individual variables in R consume the most memory? # create dummy variables for demonstration x <- 1:1000 y <- 1:10000 z <- 1:100000 # print aggregate memory usage statistics print(paste('R is using', mem...

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Error : .onLoad failed in ‘loadNamespace’ for ‘RWeka’

December 24, 2009
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Error : .onLoad failed in ‘loadNamespace’ for ‘RWeka’

After installing Weka/RWeka in R, you may get this error if you try to load RWeka in the same session: require(RWeka) Cannot create Java virtual machine (-4) Error : .onLoad failed in 'loadNamespace' for 'RWeka' Solution: Just close R and re-open it. Cause: Apparently the installation requires some initialization. Tested on R 2.10.1 on Windows

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Compare performance of machine learning classifiers in R

December 23, 2009
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Compare performance of machine learning classifiers in R

This tutorial demonstrates to the R novice how to create five machine learning models for classification and compare the performance graphically with ROC curves in one chart. For a simpler introduction, start with Plot ROC curve and lift chart in R. # ...

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Plot ROC curve and lift chart in R

December 18, 2009
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Plot ROC curve and lift chart in R

This tutorial with real R code demonstrates how to create a predictive model using cforest (Breiman’s random forests) from the package party, evaluate the predictive model on a separate set of data, and then plot the performance using ROC curves ...

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“Outlook cannot open this item.” and tasks missing

October 8, 2009
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“Outlook cannot open this item.” and tasks missing

Recently Microsoft Office Outlook 2007 started giving me the vague error message Outlook cannot open this item. The item may be damaged. The message would appear randomly throughout the day. Sometimes five error message boxes would be stacked up on top of each other. OK, but which item? What kind of item? Is it an

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Delete rows from R data frame

October 8, 2009
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Delete rows from R data frame

Deleting rows from a data frame in R is easy by combining simple operations. Let’s say you are working with the built-in data set airquality and need to remove rows where the ozona is NA (also called null, blank or missing). The method is a conce...

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SAS: “The query requires remerging summary statistics back with the original data”

September 22, 2009
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SAS: “The query requires remerging summary statistics back with the original data”

Coming from a background writing SQL code directly for “real” RDBMS (Microsoft SQL Server, MySQL, and SQLite), I was initially confused when SAS would give me the following ‘note’ for a simple summary PROC SQL query: 429 proc sql; 430 create table undel_monthly as 431 select 432 year(date) as year, 433 month(date) as month, 434

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