Given a string, tell me how many of each character I'll need. Surprisingly useful when trying to typeset a sentence and check to see if you've enough type!

character-frequency.rb

#!/usr/bin/env ruby

puts "Gies a phrase"
str = STDIN.readline.chomp

characters = Hash.new(0)
str.each_char do |char|
  characters[char] += 1
end

characters.sort_by { |k, v| v }.reverse.each do |key, val|
  puts "#{key}: #{val}"
end

Just because I'm in a pub and therefore can't resist evil things like inject and chaining enumerable methods together...

#!/usr/bin/env ruby

puts "Gies a phrase"
STDIN.readline.chomp.each_char.inject(Hash.new(0)) do | characters, char |
  characters[char] += 1
  characters
end.sort do | (ak,av), (bk, bv) |
  bv <=> av
end.each do | char, freq |
  puts "#{char}: #{freq}"
end