instance method `slice`

Ruby on Rails 5.2.8.1

Since v2.3.18 Last seen in v5.2.8.1

Available in: v2.3.18 v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1

Compare with:

slice(*keys)

Slices a hash to include only the given keys. Returns a hash containing the given keys.

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

This is useful for limiting an options hash to valid keys before passing to a method:

def search(criteria = {})
  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))

Parameters

keys rest

Source

# File activesupport/lib/active_support/core_ext/hash/slice.rb, line 23
  def slice(*keys)
    keys.each_with_object(Hash.new) { |k, hash| hash[k] = self[k] if has_key?(k) }
  end

Defined in activesupport/lib/active_support/core_ext/hash/slice.rb line 23 · View on GitHub · Improve this page · Find usages on GitHub

Defined in Hash

Signature

Parameters