histogram-rb

Histogram

Easily create a histogram from an array of values and allow easy rendering to the terminal.

Installation

Add this line to your application's Gemfile:

gem 'histogram-rb'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install histogram-rb

Usage

Initialize a Histogram with a list of values:

histogram = Histogram.new(1000.times.map { Random.rand })

Then call render to get a print-friendly string, all parameters are optional.

histogram.render(
  title: "Uniform Distribution",
  precision: 2,
)

                              Uniform Distribution
═════════════════════════════════════════════════════════════════════════════════
    x                       x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
    x           x           x           x           x           x          x
─────────────────────────────────────────────────────────────────────────────────
 0.0-0.14   0.14-0.29   0.29-0.43   0.43-0.57   0.57-0.71   0.71-0.86   0.86-1.0
 (150)      (128)       (154)       (145)       (136)       (150)       (137)

You can use the border parameter to specify a terminal-table border class to change the output. e.g.

histogram.render(
  title: "Normal Distribution",
  precision: 2,
  border: Terminal::Table::AsciiBorder.new,
)

                               Normal Distribution
-----------+----------+----------+-----------+-----------+-----------+-----------
                                       x
                                       x
                           x           x
                           x           x
                           x           x           x
                           x           x           x           x
                           x           x           x           x
                x          x           x           x           x
                x          x           x           x           x
     x          x          x           x           x           x           x
     x          x          x           x           x           x           x
     x          x          x           x           x           x           x
-----------+----------+----------+-----------+-----------+-----------+-----------
 0.02-0.16   0.16-0.3   0.3-0.44   0.44-0.57   0.57-0.71   0.71-0.85   0.85-0.98
 (26)        (51)       (108)      (141)       (81)        (73)        (24)

Development

After checking out the repo, run bundle install to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

Testing

Running the unit tests with bundle exec rake test.

The rendering portion of the histogram is harder to test with unit tests. Instead there is a script that will allow you to render histograms easily to enable visual tests.

Examples:

bin/test bin/test -b ascii -p 2 bin/test -t "Example Title" -b thick -p 2 bin/test -t "Example Title" -b ascii -p 3 bin/test -t "Normal Distribution" -d normal -p 2 -c 10000

License

The gem is available as open source under the terms of the MIT License.