HashAtPath

Provides a simple xpath-like syntax for retrieving values from a hash.

Installation

Add this line to your application's Gemfile:

gem 'hash_at_path'

And then execute:

$ bundle

Or install it yourself as:

$ gem install hash_at_path

Usage

Paths are delimited with forward slashes and predicates are enclosed by brackets:

Predicate	Meaning
[first()]	select the first item from an array
[last()]	select the last item from an array
[0]	select an array item at a given index
[*]	all items (path selections that follow this declaration will be applied to each element)

> {'foo' => ['bar', 'baz']}.at_path('/')
{'foo' => ['bar', 'baz']}
> {'foo' => {'bar' => [{'baz' => 'bam'}, {'baz' => 'jam'}, {'baz' => ['ham']}]}}.at_path('foo/bar[*]/baz')
["bam", "jam", ["ham"]]
> {'foo' => ['bar', 'baz']}.at_path('foo[1]')
'baz'
> {'foo' => ['bar', 'baz', 'barn']}.at_path('foo[-1]')
'barn'
> {'foo' => ['bar', 'baz']}.at_path('foo[last()]')
'baz'
> {'foo' => ['bar', 'baz']}.at_path('foo[first()]')
'bar'
> {'foo' => ['bar', 'baz']}.at_path('WAT')
nil

Development

After checking out the repo, run bin/setup to install dependencies. Then, 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 to create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

1. Fork it ( https://github.com/chadfennell/hash_at_path/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request