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Welcome to FastStats! This gem is for computing stats in an efficient manner. It manages a collection of arithmetic and geometric means to help reduce the data clump code smell.

To experiment with the gem, clone it, run bundle install and then bin/console for an interactive pry session (a great Ruby REPL).

Add this line to your application's Gemfile:

gem 'fast_stats'

And then execute:

$ bundle

Or install it yourself as:

$ gem install fast_stats

Build up the arithmetic and geometric means for a metric.

mean = FastStats::Mean.new

add(val) -> value
Adds the val to the mean and returns the new n (count).
Alias: <<.

arithmetic -> value
arithmetic round: val -> value
Returns the current arithmetic mean.

geometric -> value
geometric round: val -> value
Returns the current geometric mean.

summary -> hsh
summary round: value -> hsh
Returns a Hash with the arithmetic and geometric means.

mean = FastStats::Mean.new name: "foobar"
10.times { |i| mean << i }  # or mean.add(i)

puts mean.arithmetic
# => 4.5

puts mean.arithmetic round: 2
# => 4.5

puts mean.geometric
# => 3.597297064377001

puts mean.geometric round: 3
# => 3.597

puts mean.summary
# => {
#   "arithmetic"=>4.5,
#   "geometric"=>3.597297064377001
#   }

puts mean.summary round: 3
# => {
#   "arithmetic"=>4.5,
#   "geometric"=>3.597
#   }

Collect means for multiple metrics:

means = FastStats::Means.new

add(metric_name, val) -> value
Adds the val to the name mean and returns the new n (count) for that mean.

summary -> hsh
summary round: value -> hsh
Returns a Hash of each mean's summary.

# Say you have some "post_fetcher" that is an enumerator for your posts.
means = FastStats::Means.new

post_fetcher.each do |post|
   # do stuff with post
   means.add "likes", post["like_count"]
   means.add "comments", post["share_count"]
end

means.summary
# =>
#{
#   "likes_arithmetic"=>4.888888888888889,
#   "likes_geometric"=>3.345423581422162,
#   "comments_arithmetic"=>13.636363636363637,
#   "comments_geometric"=>7.1824970648723765
#}

# You can also pass a round: value
means.summary round: 2
# =>
#{
#   "likes_arithmetic"=>4.89,
#   "likes_geometric"=>3.35,
#   "comments_arithmetic"=>13.64,
#   "comments_geometric"=>7.18
#}

Changes and plans for future changes can be found in the Change Log.

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

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/fast_stats. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

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

Everyone interacting in the FastStats project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.