Count (group by) number of line occurrences in file

24 January 2015

Here's a neat ruby script to group and count the number of occurrences of lines inside a given file.

count.rb list = IO.readlines(ARGV[0]) h = {|hash, key| hash[key] = 0} list.each {|item| h[item] += 1} h = h.sort_by { |k,v| v }.reverse h.each_with_index do |p,i| puts "(#{p[1]}) #{p[0]}" if ARGV[1] and ARGV[1].to_i <= i + 1 break end end Usage is: ruby count.rb <file> [show_at_most_n] If you have a file named "faren.txt" comprised of the following lines: test test awesome dude dude dude faren meran Running the script  with: ruby count.rb faren.txt Will yield the following result: (3) dude (2) test (1) awesome (1) faren (1) meran In addition, if you pass the "show_at_most_n" parameter (a number), it will only print that number of results. For example 2 will show the following: (3) dude (2) test

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