Spiralizer

Spiralizer converts a matrix or two-dimensional array into a string by concatenating the values in a clockwise spiral pattern, and converting all uppercase letters to lowercase.

For example, when given the matrix:

A B C D
E F G H
I J K L

Spiralizer will "spiralize" it into the following string:

"a b c d h l k j i e f g"

Installation

Add this line to your application's Gemfile:

gem 'spiralizer'

And then execute:

$ bundle

Or install it yourself as:

$ gem install spiralizer

Basic usage

You can call Spiralizer directly:

foo = [['A', 'B'], ['C', 'D']]
Spiralizer.call(foo)      # "a b d c"
Spiralizer.spiralize(foo) # also "a b d c"

Or, for greater flexibility, instantiate your own Spiralizer:

foo = [['A', 'b'], ['C', 'D']]
Spiralizer.new(data: foo, strict: false).spiralize # "a b d c"

Advanced usage

Error handling

Spiralizer exposes spiralize and spiralize!, which have different error handling behavior. The bang method will raise an exception when provided an unacceptable target, while the non-bang method will return false on error.

foo = [['A', 'B'], ['c', 'd']]
Spiralizer.new(data: foo).spiralize! # LowercaseElementError
Spiralizer.new(data: foo).spiralize  # false

bar = [['A', 'B'], [3, 4]]
Spiralizer.new(data: bar).spiralize! # NumericElementError

baz = [['A', 'B'], ['&', 'D']]
Spiralizer.new(data: baz).spiralize! # InvalidElementError

Promiscuous mode

By default, Spiralizer runs in "strict mode", which requires all matrix or array elements to be uppercase letters. Spiralize also supports promiscuous mode, with the parameter strict: false. In promiscuous mode, Sprializer does not enforce the uppercase letter requirement, and will attempt to spiralize the provided target regardless of element type.

xyzzy = [[1, 2], [3, 4]]
Spiralizer.new(data: xyzzy).spiralize! # NumericElementError
Spiralizer.new(data: xyzzy, strict: false).spiralize! # "1 2 4 3"

Development

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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/dzunk/spiralizer.

License

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