Remarks#

Why use R in Weka?

1. R is a powerful tool for preprocessing data
2. R has a huge number of libraries and keeps growing
3. R in Weka, can easily get data from, process it, and pass to Weka seamlessly

How to setup R in Weka

For Mac User

1. replace the old info.Plist with the new one given by Mark Hall

2. download and install R

3. install rJava inside R with

   install.packages(‘rJava’)

4. install Rplugin with Weka Package Manager

5. go to weka 3-8-0 folder (if it is the version you are using), and open its terminal, and

6. run the following 2 lines of codes (thanks to Michael Hall)

   export R_HOME=/Library/Frameworks/R.framework/Resources
   java -Xss10M -Xmx4096M -cp .:weka.jar weka.gui.GUIChooser

7. to make life easier, inside a directory where you want to work with weka, save the code above into a file named as weka_r.sh

8. make it executable, inside this directory’s terminal, run the code below:

   chmod a+x weka_r.sh

9. paste weka.jar from weka 3-8-0 into the directory and run the code below:

   ./weka_r.sh

Now, you are ready to go. Next time, you just need to go to the directory’s terminal and run ./weka_r.sh to start R with Weka.

How to receive data from Weka?

open Weka from terminal:
go to directory of Weka 3-8-0, open its terminal, run the following code:

java -jar weka.jar

data through Weka Explorer:

1. preprocess panel, click open file, choose a data file from weka data folder;
2. go to R console panel, type R scripts inside R console box.

data through Weka KnowledgeFlow:

1. Data mining processes panel, click DataSources to choose ArffLoader for example, click it onto canvas;
2. double-click ArffLoader to load a data file
3. Scripting panel, click RscriptExecutor onto canvas
4. option + click ArffLoader, select dataset, then click RScript Executor to link them
5. double click RScript Executor to type R script, or
6. click Settings and select R Scripting to use R console with weka’s data

Playing R Codes

1. load iris.arff with either Explorer or KnowledgeFlow;

2. try Plotting inside R Console example above

Plotting inside R Console

The following Codes can be found from Weka course

Given iris.arff is loaded in weka, inside Weka Explorer’s R console or Weka KnowledgeFlow’s R Scripting, you can play with the following codes to make beautiful plots:

library(ggplot2)

ggplot(rdata, aes(x = petallength)) + geom_density()

ggplot(rdata, aes(x = petallength)) + geom_density() + xlim(0,8)

ggplot(rdata, aes(x = petallength)) + geom_density(adjust = 0.5) + xlim(0,8)

ggplot(rdata, aes(x = petallength, color = class)) + geom_density(adjust = 0.5) + xlim(0,8)

ggplot(rdata, aes(x = petallength, color = class, fill = class)) + geom_density(adjust = 0.5) + xlim(0,8)

ggplot(rdata, aes(x = petallength, color = class, fill = class)) + geom_density(adjust = 0.5, alpha = 0.5) + xlim(0,8)





library(reshape2)
ndata = melt(rdata)
ndata

ggplot(ndata, aes(x = value, color = class, fill = class)) + geom_density(adjust = 0.5, alpha = 0.5) + xlim(0,8) + facet_grid(variable ~ .)

ggplot(ndata, aes(x = value, color = class, fill = class)) + geom_density(adjust = 0.5, alpha = 0.5) + xlim(0,8) + facet_grid(. ~ variable)

ggplot(ndata, aes(y = value, x = class, colour = class)) + geom_boxplot() + facet_grid(. ~ variable)