If I have a hash in Ruby on Rails, is there a way

2020-05-19 03:44发布

问题:

If I already have a hash, can I make it so that

h[:foo]
h['foo']

are the same? (is this called indifferent access?)

The details: I loaded this hash using the following in initializers but probably shouldn't make a difference:

SETTINGS = YAML.load_file("#{RAILS_ROOT}/config/settings.yml")

回答1:

You can just use with_indifferent_access.

SETTINGS = YAML.load_file("#{RAILS_ROOT}/config/settings.yml").with_indifferent_access


回答2:

If you have a hash already, you can do:

HashWithIndifferentAccess.new({'a' => 12})[:a]


回答3:

You can also write the YAML file that way:

--- !map:HashWithIndifferentAccess
one: 1
two: 2

after that:

SETTINGS = YAML.load_file("path/to/yaml_file")
SETTINGS[:one] # => 1
SETTINGS['one'] # => 1


回答4:

Use HashWithIndifferentAccess instead of normal Hash.

For completeness, write:

SETTINGS = HashWithIndifferentAccess.new(YAML.load_file("#{RAILS_ROOT}/config/settings.yml"­))


回答5:

You can just make a new hash of HashWithIndifferentAccess type from your hash.

hash = { "one" => 1, "two" => 2, "three" => 3 }
=> {"one"=>1, "two"=>2, "three"=>3}

hash[:one]
=> nil 
hash['one']
=> 1 


make Hash obj to obj of HashWithIndifferentAccess Class.

hash =  HashWithIndifferentAccess.new(hash)
hash[:one]
 => 1 
hash['one']
 => 1