class Hash
# Returns a new hash with all keys converted using the block operation.
#
# hash = { name: 'Rob', age: '28' }
#
# hash.transform_keys{ |key| key.to_s.upcase }
# # => {"NAME"=>"Rob", "AGE"=>"28"}
def transform_keys
result = {}
each_key do |key|
result[yield(key)] = self[key]
end
result
end
# Destructively convert all keys using the block operations.
# Same as transform_keys but modifies +self+.
def transform_keys!
keys.each do |key|
self[yield(key)] = delete(key)
end
self
end
# Returns a new hash with all keys converted to strings.
#
# hash = { name: 'Rob', age: '28' }
#
# hash.stringify_keys
# # => {"name"=>"Rob", "age"=>"28"}
def stringify_keys
transform_keys{ |key| key.to_s }
end
# Destructively convert all keys to strings. Same as
# +stringify_keys+, but modifies +self+.
def stringify_keys!
transform_keys!{ |key| key.to_s }
end
# Returns a new hash with all keys converted to symbols, as long as
# they respond to +to_sym+.
#
# hash = { 'name' => 'Rob', 'age' => '28' }
#
# hash.symbolize_keys
# # => {:name=>"Rob", :age=>"28"}
def symbolize_keys
transform_keys{ |key| key.to_sym rescue key }
end
alias_method :to_options, :symbolize_keys
# Destructively convert all keys to symbols, as long as they respond
# to +to_sym+. Same as +symbolize_keys+, but modifies +self+.
def symbolize_keys!
transform_keys!{ |key| key.to_sym rescue key }
end
alias_method :to_options!, :symbolize_keys!
# Validate all keys in a hash match <tt>*valid_keys</tt>, raising
# ArgumentError on a mismatch.
#
# Note that keys are treated differently than HashWithIndifferentAccess,
# meaning that string and symbol keys will not match.
#
# { name: 'Rob', years: '28' }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: :years. Valid keys are: :name, :age"
# { name: 'Rob', age: '28' }.assert_valid_keys('name', 'age') # => raises "ArgumentError: Unknown key: :name. Valid keys are: 'name', 'age'"
# { name: 'Rob', age: '28' }.assert_valid_keys(:name, :age) # => passes, raises nothing
def assert_valid_keys(*valid_keys)
valid_keys.flatten!
each_key do |k|
unless valid_keys.include?(k)
raise ArgumentError.new("Unknown key: #{k.inspect}. Valid keys are: #{valid_keys.map(&:inspect).join(', ')}")
end
end
end
# Returns a new hash with all keys converted by the block operation.
# This includes the keys from the root hash and from all
# nested hashes and arrays.
#
# hash = { person: { name: 'Rob', age: '28' } }
#
# hash.deep_transform_keys{ |key| key.to_s.upcase }
# # => {"PERSON"=>{"NAME"=>"Rob", "AGE"=>"28"}}
def deep_transform_keys(&block)
_deep_transform_keys_in_object(self, &block)
end
# Destructively convert all keys by using the block operation.
# This includes the keys from the root hash and from all
# nested hashes and arrays.
def deep_transform_keys!(&block)
_deep_transform_keys_in_object!(self, &block)
end
# Returns a new hash with all keys converted to strings.
# This includes the keys from the root hash and from all
# nested hashes and arrays.
#
# hash = { person: { name: 'Rob', age: '28' } }
#
# hash.deep_stringify_keys
# # => {"person"=>{"name"=>"Rob", "age"=>"28"}}
def deep_stringify_keys
deep_transform_keys{ |key| key.to_s }
end
# Destructively convert all keys to strings.
# This includes the keys from the root hash and from all
# nested hashes and arrays.
def deep_stringify_keys!
deep_transform_keys!{ |key| key.to_s }
end
# Returns a new hash with all keys converted to symbols, as long as
# they respond to +to_sym+. This includes the keys from the root hash
# and from all nested hashes and arrays.
#
# hash = { 'person' => { 'name' => 'Rob', 'age' => '28' } }
#
# hash.deep_symbolize_keys
# # => {:person=>{:name=>"Rob", :age=>"28"}}
def deep_symbolize_keys
deep_transform_keys{ |key| key.to_sym rescue key }
end
# Destructively convert all keys to symbols, as long as they respond
# to +to_sym+. This includes the keys from the root hash and from all
# nested hashes and arrays.
def deep_symbolize_keys!
deep_transform_keys!{ |key| key.to_sym rescue key }
end
private
# support methods for deep transforming nested hashes and arrays
def _deep_transform_keys_in_object(object, &block)
case object
when Hash
object.each_with_object({}) do |(key, value), result|
result[yield(key)] = _deep_transform_keys_in_object(value, &block)
end
when Array
object.map {|e| _deep_transform_keys_in_object(e, &block) }
else
object
end
end
def _deep_transform_keys_in_object!(object, &block)
case object
when Hash
object.keys.each do |key|
value = object.delete(key)
object[yield(key)] = _deep_transform_keys_in_object!(value, &block)
end
object
when Array
object.map! {|e| _deep_transform_keys_in_object!(e, &block)}
else
object
end
end
end
