Install without Bundler:
gem install simple_stats --no-ri --no-rdoc
Install with Bundler:
gem "simple_stats"Then get some statistics on arrays or enumerables:
require 'rubygems' # if not using Bundler
require 'simple_stats'
samples = [3, 1, 0, 8, 2, 2, 3, 9]
samples.sum # 28
samples.mean # 3.5
samples.median # 2.5
samples.modes # [2, 3]
samples.frequencies
# {
# 0 => 1,
# 1 => 1,
# 2 => 2,
# 3 => 2,
# 8 => 1,
# 9 => 1
# }
samples.sorted_frequencies
# most common elements first
# [
# [2, 2],
# [3, 2],
# [0, 1],
# [1, 1],
# [8, 1],
# [9, 1]
# ]
# of course, you can take modes/frequencies on non-numeric data...
"banana nanny!".chars.modes
# ["n"]
"banana nanny!".chars.frequencies
# {
# " " => 1,
# "! "=> 1,
# "a" => 4,
# "b" => 1,
# "n" => 5,
# "y" => 1
# }
"banana nanny!".chars.sorted_frequencies
# [
# ["n", 5],
# ["a", 4],
# [" ", 1],
# ["!", 1],
# ["b", 1],
# ["y", 1]
# ]
# sum of nothing is 0
[].sum # 0
# mean and median of nothing is undefined
[].mean # nil
[].median # nil
# modes and frequencies return empty containers
[].modes # []
[].frequencies # {}
[].sorted_frequencies # []
# if elements are present, mean and median always return floats
[1, 2, 3].mean # 2.0
[1, 2, 3].median # 2.0
[1, 2, 3, 4].mean # 2.5
[1, 2, 3, 4].median # 2.5
# sum, mode, and frequencies preserve the object class
[1, 2, 3].sum # 6
[1.0, 2.0, 3.0].sum # 6.0
# but no guarantees on class here:
[2.0, 2, 1].modes # [2]
[2, 2.0, 1].modes # [2.0]Need something added? Open an issue. Or, even better, code it yourself and send a pull request:
# fork it on github, then clone:
git clone git@github.com:your_username/simple_stats.git
bundle install
rspec
# hack away
git push
# then make a pull request
Public domain. (I, Brian Hempel, the original author release this code to the public domain. February 10, 2012.)