https://github.com/oleander/is_prime

Is the given number a prime number?
https://github.com/oleander/is_prime

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Is the given number a prime number?

• Host: GitHub
• URL: https://github.com/oleander/is_prime
• Owner: oleander
• Created: 2011-05-16T21:30:09.000Z (over 13 years ago)
• Default Branch: master
• Last Pushed: 2011-05-16T21:31:18.000Z (over 13 years ago)
• Last Synced: 2024-03-14T13:02:51.685Z (10 months ago)
• Language: Ruby
• Homepage: https://github.com/oleander/is_prime
• Size: 89.8 KB
• Stars: 1
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# is_prime

Is the given number a prime number?

Follow me on [Twitter](http://twitter.com/linusoleander) or [Github](https://github.com/oleander/) for more info and updates.

## How to use

  

```` ruby

require "is_prime"

3.prime? # => true

4.prime? # => false

````

## What algorithm is being used?

The implementation is just one line.

```` ruby

('1' * N) !~ /^1?$|^(11+?)\1+$/

````

Read more about it [here](http://www.noulakaz.net/weblog/2007/03/18/a-regular-expression-to-check-for-prime-numbers/).

## How to install

    [sudo] gem install is_prime

## Requirements

*is_prime* is tested in Mac OS X 10.6.6, 10.6.7 using Ruby 1.8.7, 1.9.2.

## License

*is_prime* is released under the *MIT license*.