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https://github.com/brianhempel/simple_stats
Finally, simple mean, median, mode, sum, and frequencies for Ruby arrays and enumerables!
https://github.com/brianhempel/simple_stats
Last synced: about 1 month ago
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Finally, simple mean, median, mode, sum, and frequencies for Ruby arrays and enumerables!
- Host: GitHub
- URL: https://github.com/brianhempel/simple_stats
- Owner: brianhempel
- Created: 2012-02-10T19:57:16.000Z (almost 13 years ago)
- Default Branch: master
- Last Pushed: 2013-12-16T03:44:06.000Z (almost 11 years ago)
- Last Synced: 2024-08-09T00:26:22.776Z (4 months ago)
- Language: Ruby
- Homepage:
- Size: 105 KB
- Stars: 26
- Watchers: 3
- Forks: 5
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- data-science-with-ruby - simple_stats
README
# SimpleStats [](http://travis-ci.org/brianhempel/simple_stats)
Install without Bundler:
gem install simple_stats --no-ri --no-rdoc
Install with Bundler:
```ruby
gem "simple_stats"
```
Then get some statistics on arrays or enumerables:
```ruby
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]
```
## Mapping
If the thing you want stats on is buried in your objects, you can pass a block to any SimpleStats method.
```ruby
# these two lines do the same thing
cities.mean {|city| city.population}
cities.map {|city| city.population}.mean
# other examples
cities.sum(&:public_school_count)
cities.mean(&:public_school_count)
cities.frequencies(&:professional_team_count)
# more complicated examples
cities.median {|city| city.municipal_income / city.schools.sum(&:students)}
cities.map(&:schools).flatten.modes(&:team_name) # most common school sports team name
cities.map(&:professional_teams).flatten.sorted_frequencies(&:kind) # number of different kinds of sports teams
```
## Interaction with other gems
If any of SimpleStats' methods are already defined on Enumerable, SimpleStats _will not_ replace them with its own definition. In particular, ActiveSupport [defines a `sum` method](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/core_ext/enumerable.rb). If both ActiveSupport and SimpleStats are used, the `sum` method will come from ActiveSupport. Don't worry, ActiveSupport and SimpleStats should work fine together.
## Help make it better!
Need something added? [Open an issue](https://github.com/brianhempel/simple_stats/issues). Or, even better, code it yourself and send a pull request:
# fork it on github, then clone:
git clone [email protected]:your_username/simple_stats.git
bundle install
rspec
# hack away
git push
# then make a pull request
## License
Public domain. (I, Brian Hempel, the original author release this code to the public domain. February 10, 2012.)