Sparklines in Ruby

spark.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-

# prints a sparkline in the terminal using the supplied list of numbers
# examples:
#   spark.rb 10 20 30 100 90 80
#   spark.rb 1 2 0.4 0.1 1.3 0.7

@ticks = %w[▁ ▂ ▃ ▄ ▅ ▆ ▇]
values = ARGV.map { |x| x.to_f }
min, range, scale = values.min, values.max - values.min, @ticks.length - 1
puts values.map { |x| @ticks[(((x - min) / range) * scale).round] }.join

This gives smoother ticks:

@ticks = %w[▁ ▂ ▃ ▄ ▅ ▆ ▇]

Indeed. Thanks!

Small problem if range = 0...

You're right @newfoundresearch. However, a sparkline for a dataset with a range of 0 wouldn't be very interesting anyway, would it? :)

@ticks = %w[▁ ▂ ▃ ▄ ▅ ▆ ▇]
values = ARGV.map { |x| x.to_f }
min, range, scale = values.min, values.max - values.min, @ticks.length - 1
if !(range == 0)
  puts values.map { |x| @ticks[(((x - min) / range) * scale).round] }.join
else
  puts values.map { |x| @ticks[1] }.join
end

Just in case range == 0