https://github.com/ruby/set
This library provides the Set class, which deals with a collection of unordered values with no duplicates.
https://github.com/ruby/set
ruby
Last synced: 11 months ago
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This library provides the Set class, which deals with a collection of unordered values with no duplicates.
- Host: GitHub
- URL: https://github.com/ruby/set
- Owner: ruby
- License: bsd-2-clause
- Created: 2020-05-22T11:16:18.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2025-05-12T08:29:40.000Z (12 months ago)
- Last Synced: 2025-05-12T08:55:49.080Z (12 months ago)
- Topics: ruby
- Language: Ruby
- Homepage:
- Size: 240 KB
- Stars: 22
- Watchers: 35
- Forks: 15
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.txt
- Codeowners: .github/CODEOWNERS
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README
# Set
This library provides the Set class, which deals with a collection of
unordered values with no duplicates. It is a hybrid of Array's
intuitive inter-operation facilities and Hash's fast lookup.
The method `to_set` is added to Enumerable for convenience.
Set implements a collection of unordered values with no duplicates.
This is a hybrid of Array's intuitive inter-operation facilities and
Hash's fast lookup.
Set is easy to use with Enumerable objects (implementing `each`).
Most of the initializer methods and binary operators accept generic
Enumerable objects besides sets and arrays. An Enumerable object can
be converted to Set using the `to_set` method.
Set uses Hash as storage, so you must note the following points:
* Equality of elements is determined according to Object#eql? and
Object#hash. Use Set#compare_by_identity to make a set compare its
elements by their identity.
* Set assumes that the identity of each element does not change while
it is stored. Modifying an element of a set will render the set to
an unreliable state.
* When a string is to be stored, a frozen copy of the string is stored
instead unless the original string is already frozen.
### Comparison
The comparison operators `<`, `>`, `<=`, and `>=` are implemented as
shorthand for the {proper_,}{subset?,superset?} methods. The `<=>`
operator reflects this order, or return `nil` for sets that both have
distinct elements (`{x, y}` vs. `{x, z}` for example).
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'set'
```
And then execute:
$ bundle install
Or install it yourself as:
$ gem install set
## Usage
```ruby
require 'set'
s1 = Set[1, 2] #=> #
s2 = [1, 2].to_set #=> #
s1 == s2 #=> true
s1.add("foo") #=> #
s1.merge([2, 6]) #=> #
s1.subset?(s2) #=> false
s2.subset?(s1) #=> true
```
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/set.
Feature requests should also go to https://bugs.ruby-lang.org/ for wider audience and discussion.
## License
The gem is available as open source under either the terms of the [2-Clause BSD License](https://opensource.org/licenses/BSD-2-Clause). When bundled with Ruby, you can distribute/modify this program under the same terms of [Ruby](https://www.ruby-lang.org/en/about/license.txt).