From: "Brian Schröder" <ruby@...>
Date: 2004-12-09T02:16:20+09:00
Subject: Re: count unique records

On Thu, 9 Dec 2004 01:37:36 +0900
pustoi@spils.lv wrote:

> Hello,
> 
> Is there method in ruby like "uniq -c" command in Unix ?
> uniq -c, --count prefix lines by the number of occurrences
> 
> Thnx
> 
> 

You can implement uniq -c like this:


#!/usr/bin/ruby

(ARGF.read.split($/) << nil).inject([nil, 0]) do | (last_line, count), line |
  if last_line and line != last_line
    puts(("%7d " % count) + last_line)
    count = 0
  end
  [line, count+1]
end


Use:


bschroed@black:~/svn/projekte/ruby-things $ cat send.rb | uniq -c
      1 class A
      1   def send_it method_name
      1     send(method_name, "Send from #{self}")
      1   end
      1 end
      1 
      1 class B < A
      1   def select(msg)
      1     puts "Received: #{msg}"
      1   end
      1 end
      1 
      1 b = B.new
      1 b.send_it(:select)
bschroed@black:~/svn/projekte/ruby-things $ cat send.rb | ./uniq-count
      1 class A
      1   def send_it method_name
      1     send(method_name, "Send from #{self}")
      1   end
      1 end
      1 
      1 class B < A
      1   def select(msg)
      1     puts "Received: #{msg}"
      1   end
      1 end
      1 
      1 b = B.new
      1 b.send_it(:select)
bschroed@black:~/svn/projekte/ruby-things $ cat send.rb | sort | uniq -c
      2 
      1 b = B.new
      1 b.send_it(:select)
      1 class A
      1 class B < A
      1   def select(msg)
      1   def send_it method_name
      2 end
      2   end
      1     puts "Received: #{msg}"
      1     send(method_name, "Send from #{self}")
bschroed@black:~/svn/projekte/ruby-things $ cat send.rb | sort | ./uniq-count
      2 
      1 b = B.new
      1 b.send_it(:select)
      1 class A
      1 class B < A
      1   def select(msg)
      1   def send_it method_name
      2 end
      2   end
      1     puts "Received: #{msg}"
      1     send(method_name, "Send from #{self}")


regards,

Brian

-- 
Brian Schr�der
http://www.brian-schroeder.de/