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