Class: Hash

Inherits:
Object
  • Object
show all
Defined in:
lib/ext/hash/keys.rb,
lib/ext/hash/slice.rb,
lib/ext/hash/except.rb

Instance Method Summary collapse

Instance Method Details

#assert_valid_keys(*valid_keys) ⇒ Object

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

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# 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

#deep_stringify_keysObject

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"}}

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# File 'lib/ext/hash/keys.rb', line 111

def deep_stringify_keys
  deep_transform_keys(&:to_s)
end

#deep_stringify_keys!Object

Destructively converts all keys to strings. This includes the keys from the root hash and from all nested hashes and arrays.


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# File 'lib/ext/hash/keys.rb', line 118

def deep_stringify_keys!
  deep_transform_keys!(&:to_s)
end

#deep_symbolize_keysObject

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"}}

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# File 'lib/ext/hash/keys.rb', line 130

def deep_symbolize_keys
  deep_transform_keys{ |key| key.to_sym rescue key }
end

#deep_symbolize_keys!Object

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.


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# File 'lib/ext/hash/keys.rb', line 137

def deep_symbolize_keys!
  deep_transform_keys!{ |key| key.to_sym rescue key }
end

#deep_transform_keys(&block) ⇒ Object

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"}}

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# File 'lib/ext/hash/keys.rb', line 92

def deep_transform_keys(&block)
  _deep_transform_keys_in_object(self, &block)
end

#deep_transform_keys!(&block) ⇒ Object

Destructively converts all keys by using the block operation. This includes the keys from the root hash and from all nested hashes and arrays.


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# File 'lib/ext/hash/keys.rb', line 99

def deep_transform_keys!(&block)
  _deep_transform_keys_in_object!(self, &block)
end

#except(*keys) ⇒ Object

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))

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# File 'lib/ext/hash/except.rb', line 10

def except(*keys)
  dup.except!(*keys)
end

#except!(*keys) ⇒ Object

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 }

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# File 'lib/ext/hash/except.rb', line 18

def except!(*keys)
  keys.each { |key| delete(key) }
  self
end

#extract!(*keys) ⇒ Object

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}

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# 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

#slice(*keys) ⇒ Object

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))

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# 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

#slice!(*keys) ⇒ Object

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}

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# 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

#stringify_keysObject

Returns a new hash with all keys converted to strings.

hash = { name: 'Rob', age: '28' }

hash.stringify_keys
# => {"name"=>"Rob", "age"=>"28"}

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# File 'lib/ext/hash/keys.rb', line 37

def stringify_keys
  transform_keys(&:to_s)
end

#stringify_keys!Object

Destructively converts all keys to strings. Same as stringify_keys, but modifies self.


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# File 'lib/ext/hash/keys.rb', line 43

def stringify_keys!
  transform_keys!(&:to_s)
end

#symbolize_keysObject Also known as: to_options

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"}

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# File 'lib/ext/hash/keys.rb', line 54

def symbolize_keys
  transform_keys{ |key| key.to_sym rescue key }
end

#symbolize_keys!Object Also known as: to_options!

Destructively converts all keys to symbols, as long as they respond to to_sym. Same as symbolize_keys, but modifies self.


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# File 'lib/ext/hash/keys.rb', line 61

def symbolize_keys!
  transform_keys!{ |key| key.to_sym rescue key }
end

#transform_keysObject

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"}

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# 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

#transform_keys!Object

Destructively converts all keys using the block operations. Same as transform_keys but modifies self.


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# 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