Module: Gorillib::Hashlike::Slice

Included in:
Hash
Defined in:
lib/gorillib/hashlike/slice.rb

Instance Method Summary collapse

Instance Method Details

#slice(*allowed_keys) ⇒ Object

Slice a hash to include only the given allowed_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))

If you have an array of keys you want to limit to, you should splat them:

valid_keys = [:mass, :velocity, :time]
search(options.slice(*valid_keys))



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# File 'lib/gorillib/hashlike/slice.rb', line 17

def slice(*allowed_keys)
  allowed_keys = allowed_keys.map!{|key| convert_key(key) } if respond_to?(:convert_key)
  hash = self.class.new
  allowed_keys.each{|k| hash[k] = self[k] if has_key?(k) }
  hash
end

#slice!(*allowed_keys) ⇒ Object

Replaces the hash with only the given allowed_keys. Returns a hash containing the removed key/value pairs

Examples:

hsh = {:a => 1, :b => 2, :c => 3, :d => 4}
hsh.slice!(:a, :b)
# => {:c => 3, :d =>4}
hsh
# => {:a => 1, :b => 2}


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# File 'lib/gorillib/hashlike/slice.rb', line 32

def slice!(*allowed_keys)
  allowed_keys = allowed_keys.map!{|key| convert_key(key) } if respond_to?(:convert_key)
  omit = slice(*self.keys - allowed_keys)
  hash = slice(*allowed_keys)
  replace(hash)
  omit
end