Example: Gettysburg

The code and output belowdemonstrates some of RinRuby’s features. Ruby code counts the number ofoccurences of each word in Lincoln’s Gettysburg Address and ﬁltersout those occurring less than three times or shorter than four letters.R code — through the RinRuby library — produces a bar plot of the mostfrequent words and computes the correlation between the length of aword and the usage frequency. Finally, the computed correlation isprinted by Ruby. The text for the "gettysburg.txt" file is here.

Code:

   tally = Hash.new(0)
   File.open('gettysburg.txt').each_line do |line|
line.downcase.split(/\W+/).each { |w| tally[w] += 1 }
   end
   total = tally.values.inject { |sum,count| sum + count }
   tally.delete_if { |key,count| count < 3 || key.length < 4 }

   require "rinruby"
   R.keys, R.counts = tally.keys, tally.values

   R.eval <<EOF
names(counts) <- keys
      barplot(rev(sort(counts)),main="Frequency of Non-Trivial Words",las=2)
mtext("Among the #{total} words in the Gettysburg Address",3,0.45)
rho <- round(cor(nchar(keys),counts),4)
   EOF

   puts "The correlation between word length and frequency is #{R.rho}."

Output:

The correlation between word length and frequency is -0.2779.

Subpages (1):gettysburg.txt