Michael Sjoerdsma sfu technical writing

http://www.sfu.ca/immr/pmp/people.htm

Michael is currently a faculty member in the School of Engineering Science
at Simon Fraser University teaching courses related to technical writing,
group dynamics, graphical communication, and ethics and law.nique Process Feaures

Ruby create a class object with name determined at runtime, calling dynamic methods

http://ruby-doc.org/docs/ProgrammingRuby/html/ospace.html

Calling a method unknown during compile time.

So we want to call a method but we only get the method's name at runtime, use the 'send' method
ruby-1.8.7-p302 > 'John Coltran'.send('length')
 => 12


or using 'method' to call it later

or 'eval'

r = eval "'John Coltran'.length"
 => 12

-------------------------------------

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/190828

$ irb
ruby-1.8.7-p302 > b=Object::const_get('String').new()
 => ""
ruby-1.8.7-p302 > b
 => ""
ruby-1.8.7-p302 > b.class
 => String

# Print all User tuples
>  b = Object::const_get('User').new()
>  puts b.class
 => String
>  puts b.class.all
#


$ rails console < my_script_helper.rb


--------class----------------

# The Greeter class

class Greeter

  def initialize(name)

    @name = name.capitalize

  end

  def salute

    puts "Hello #{@name}!"

  end

end

# Create a new object

g = Greeter.new("world")

# Output "Hello World!"

g.salute

vs
--------module-------------
http://ruby-doc.org/core/classes/Module.html
 A Module is a collection of methods and constants.

module Mod
     alias_method :orig_exit, :exit
     def exit(code=0)
       puts "Exiting with code #{code}"
       orig_exit(code)
     end
   end
   include Mod
   exit(99)

R blogs and gallery

http://addictedtor.free.fr/graphiques/

http://www.statmethods.net/input/missingdata.html
# create new dataset without missing data
newdata <- na.omit(mydata)  
 

Reshaping data

http://www.statmethods.net/management/reshape.html




# example of melt function
library(reshape)
mdata <- melt(mydata, id=c("id","time")) 

http://www.statmethods.net/graphs/creating.html

# Creating a Graph with a linear model regression line
attach(mtcars)
plot(wt, mpg)
abline(lm(mpg~wt))
title("Regression of MPG on Weight")




http://www.statmethods.net/graphs/density.html

# Filled Density Plot
d <- density(mtcars$mpg)
plot(d, main="Kernel Density of Miles Per Gallon")
polygon(d, col="red", border="blue") 

Comparing Groups VIA Kernal Density

The sm.density.compare( ) function in the sm package allows you to superimpose the kernal density plots of two or more groups. The format is sm.density.compare(x, factor) where x is a numeric vector and factor is the grouping variable.
# Compare MPG distributions for cars with
# 4,6, or 8 cylinders
library(sm)
attach(mtcars)

# create value labels
cyl.f <- factor(cyl, levels= c(4,6,8),
  labels = c("4 cylinder", "6 cylinder", "8 cylinder"))

# plot densities
sm.density.compare(mpg, cyl, xlab="Miles Per Gallon")
title(main="MPG Distribution by Car Cylinders")

# add legend via mouse click
colfill<-c(2:(2+length(levels(cyl.f))))
legend(locator(1), levels(cyl.f), fill=colfill)


http://yihui.name/en/page/2/
http://yihui.name/en/2009/06/creating-tag-cloud-using-r-and-flash-javascript-swfobject/#more-224 - Tag Cloud

Side by side plot

# png(width = 500, height = 300)

x = rep(0, 1000)

par(mfrow = c(1, 2), mar = c(4, 4, 0.1, 0.1))

plot(density(x), main = "")

plot(density(x), main = "")

rug(jitter(x))

# dev.off()

http://yihui.name/en/2008/09/to-see-a-circle-in-a-pile-of-sand/#more-52




# transparent colors (alpha = 0.1)

plot(x, col = rgb(0, 0, 0, 0.1))

http://processtrends.com/RClimate.htm 

## Use regexp to replace all the occurences of **** with NA
lines2 <- gsub("\\*{3,5}", " NA", lines, perl=TRUE)

## Select monthly data in first 13 columns
df <- df[,1:13]

## Remove rows where Year=NA from the dataframe
df <- df [!is.na(df$Year),] 

Using lattice in R

http://www.his.sunderland.ac.uk/~cs0her/Statistics/UsingLatticeGraphicsInR.htm

## Multiple variables in formula for grouped displays

xyplot(Sepal.Length + Sepal.Width ~ Petal.Length + Petal.Width | Species, 
       data = iris, scales = "free", layout = c(2, 2),
       auto.key = list(x = .6, y = .7, corner = c(0, 0))) 

## user defined panel functions

states <- data.frame(state.x77,
                     state.name = dimnames(state.x77)[[1]], 
                     state.region = state.region) 
xyplot(Murder ~ Population | state.region, data = states, 
       groups = state.name, 
       panel = function(x, y, subscripts, groups)  
       ltext(x = x, y = y, label = groups[subscripts], cex=1,
             fontfamily = "HersheySans"))  

http://learnr.wordpress.com/2009/08/18/ggplot2-version-of-figures-in-lattice-multivariate-data-visualization-with-r-part-13/

http://data.princeton.edu/R/gettingStarted.html

http://www.r-bloggers.com/5-minute-analysis-in-r-case-shiller-indices/ 

http://lmdvr.r-forge.r-project.org/figures/figures.html 

Lucid update Ubuntu splash in grub

http://anonir.wordpress.com/2010/08/08/ubuntu-lucid-disable-boot-splash/

Open /etc/default/grub for editing and remove “quiet splash” options from the GRUB_CMDLINE_LINUX_DEFAULT property.
For example, if your grub has this line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
Change it to this:
GRUB_CMDLINE_LINUX_DEFAULT=""
Then run this command to update grub2:
sudo update-grub

R removing NA

http://www.opensubscriber.com/message/r-help@stat.math.ethz.ch/7268077.html

> df<-data.frame(name=c('a','b'), age=c('1','2'))
> if (any(apply(df,1,function(x) any(is.na(x)))) == TRUE)  { r <- df[-which(apply(df,1,function(x) any(is.na(x)))),] }  else { r <- df }
> r
  name age
1    a   1
2    b   2

> df<-data.frame(name=c('a','b'), age=c('1',NA))
> df
  name  age
1    a    1
2    b
> if (any(apply(df,1,function(x) any(is.na(x)))) == TRUE)  { r <- df[-which(apply(df,1,function(x) any(is.na(x)))),] }  else { r <- df }
> r
  name age
1    a   1

## Remove rows where Year=NA from the dataframe
df <- df [!is.na(df$Year),] 

tm package on R

R 2.11 is needed by tm (tm_0.5-4.1.tar.gz) but only R 2.10 is in the lucid ubuntu repo

so

http://ubuntuforums.org/showthread.php?t=639710

deb http://cran.r-project.org/bin/linux/ubuntu lucid/

gpg --keyserver subkeys.pgp.net --recv-key E2A11821 
   gpg -a --export E2A11821 | sudo apt-key add - 

My R libraries installed to

$HOME/R/x86_64-pc-linux-gnu-library/2.11

So you need to add this path in the 'R console' Run configuration

then I got a 'checking for xml2-config... no' error when doing

   install.packages('XML')

so do 

$ sudo apt-get install libxml2-dev

Ubuntu 10.04.1 LTS Lucid Lynx

#enable canonical archive in /etc/apt/sources.list
sudo apt-get install sun-java6-jdk

sudo apt-get install r-base

sudo apt-get update && sudo apt-get install cairo-dock cairo-dock-plug-ins

Ubuntu Intrepid AMD64

https://launchpad.net/ubuntu/intrepid/amd64

/var/lib/dpkg$ sudo cp status-old2 status

R inspection commands

class()
inspect()
summary()
head()

/usr/bin/ld: cannot find -lgfortran

$ ld -lgfortran
ld: cannot find -lgfortran

$ sudo ln -s /usr/lib/libgfortran.so.3.0.0 /usr/lib/libgfortran.so

$ ld -lgfortran
ld: warning: cannot find entry symbol _start; not setting start address

Idempotence

idempotent - they can be applied multiple times without changing the result.

School, Life, Lessons

" The difference between school and life? In school, you're taught a lesson and the given a test. In life, you're given a test that teaches you a lesson" - Tom Bodett