Module: ActiveSupport::CoreExtensions::Hash::Slice

Included in:
Hash
Defined in:
lib/active_support/core_ext/hash/slice.rb

Overview

Slice a hash to include only the given keys. This is useful for limiting an options hash to valid keys before passing to a method:

def search(criteria = {})
  assert_valid_keys(:mass, :velocity, :time)
end

search(options.slice(:mass, :velocity, :time))

Instance Method Summary collapse

Instance Method Details

#slice(*keys) ⇒ Object

Returns a new hash with only the given keys.


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# File 'lib/active_support/core_ext/hash/slice.rb', line 16

def slice(*keys)
  allowed = Set.new(respond_to?(:convert_key) ? keys.map { |key| convert_key(key) } : keys)
  reject { |key,| !allowed.include?(key) }
end

#slice!(*keys) ⇒ Object

Replaces the hash with only the given keys.


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# File 'lib/active_support/core_ext/hash/slice.rb', line 22

def slice!(*keys)
  replace(slice(*keys))
end