class Hash
Public Instance Methods
Validates all keys in a hash match *valid_keys
, 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
# File lib/ext/hash/keys.rb, line 75 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 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"}}
# File lib/ext/hash/keys.rb, line 111 def deep_stringify_keys deep_transform_keys(&:to_s) end
Destructively converts all keys to strings. This includes the keys from the root hash and from all nested hashes and arrays.
# File lib/ext/hash/keys.rb, line 118 def deep_stringify_keys! deep_transform_keys!(&: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"}}
# File lib/ext/hash/keys.rb, line 130 def deep_symbolize_keys deep_transform_keys{ |key| key.to_sym rescue key } end
Destructively converts 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.
# File lib/ext/hash/keys.rb, line 137 def deep_symbolize_keys! deep_transform_keys!{ |key| key.to_sym rescue key } 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"}}
# File lib/ext/hash/keys.rb, line 92 def deep_transform_keys(&block) _deep_transform_keys_in_object(self, &block) end
Destructively converts all keys by using the block operation. This includes the keys from the root hash and from all nested hashes and arrays.
# File lib/ext/hash/keys.rb, line 99 def deep_transform_keys!(&block) _deep_transform_keys_in_object!(self, &block) end
Returns a hash that includes everything except given keys.
hash = { a: true, b: false, c: nil } hash.except(:c) # => { a: true, b: false } hash.except(:a, :b) # => { c: nil } hash # => { a: true, b: false, c: nil }
This is useful for limiting a set of parameters to everything but a few known toggles:
@person.update(params[:person].except(:admin))
# File lib/ext/hash/except.rb, line 10 def except(*keys) dup.except!(*keys) end
Removes the given keys from hash and returns it.
hash = { a: true, b: false, c: nil } hash.except!(:c) # => { a: true, b: false } hash # => { a: true, b: false }
# File lib/ext/hash/except.rb, line 18 def except!(*keys) keys.each { |key| delete(key) } self end
Removes and returns the key/value pairs matching the given keys.
{ a: 1, b: 2, c: 3, d: 4 }.extract!(:a, :b) # => {:a=>1, :b=>2} { a: 1, b: 2 }.extract!(:a, :x) # => {:a=>1}
# File lib/ext/hash/slice.rb, line 45 def extract!(*keys) keys.each_with_object(self.class.new) { |key, result| result[key] = delete(key) if has_key?(key) } end
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))
# File lib/ext/hash/slice.rb, line 21 def slice(*keys) keys.map! { |key| convert_key(key) } if respond_to?(:convert_key, true) keys.each_with_object(self.class.new) { |k, hash| hash[k] = self[k] if has_key?(k) } end
Replaces the hash with only the given keys. Returns a hash containing the removed key/value pairs.
{ a: 1, b: 2, c: 3, d: 4 }.slice!(:a, :b) # => {:c=>3, :d=>4}
# File lib/ext/hash/slice.rb, line 31 def slice!(*keys) keys.map! { |key| convert_key(key) } if respond_to?(:convert_key, true) omit = slice(*self.keys - keys) hash = slice(*keys) hash.default = default hash.default_proc = default_proc if default_proc replace(hash) omit end
Returns a new hash with all keys converted to strings.
hash = { name: 'Rob', age: '28' } hash.stringify_keys # => {"name"=>"Rob", "age"=>"28"}
# File lib/ext/hash/keys.rb, line 37 def stringify_keys transform_keys(&:to_s) end
Destructively converts all keys to strings. Same as stringify_keys
, but modifies self
.
# File lib/ext/hash/keys.rb, line 43 def stringify_keys! transform_keys!(&: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"}
# File lib/ext/hash/keys.rb, line 54 def symbolize_keys transform_keys{ |key| key.to_sym rescue key } end
Destructively converts all keys to symbols, as long as they respond to to_sym
. Same as symbolize_keys
, but modifies self
.
# File lib/ext/hash/keys.rb, line 61 def symbolize_keys! transform_keys!{ |key| key.to_sym rescue key } end
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"}
If you do not provide a block
, it will return an Enumerator for chaining with other methods:
hash.transform_keys.with_index { |k, i| [k, i].join } # => {"name0"=>"Rob", "age1"=>"28"}
# File lib/ext/hash/keys.rb, line 12 def transform_keys return enum_for(:transform_keys) { size } unless block_given? result = self.class.new each_key do |key| result[yield(key)] = self[key] end result end
Destructively converts all keys using the block
operations. Same as transform_keys
but modifies self
.
# File lib/ext/hash/keys.rb, line 23 def transform_keys! return enum_for(:transform_keys!) { size } unless block_given? keys.each do |key| self[yield(key)] = delete(key) end self end
Private Instance Methods
support methods for deep transforming nested hashes and arrays
# File lib/ext/hash/keys.rb, line 143 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
# File lib/ext/hash/keys.rb, line 156 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