Let's say you want an object's class name in Ruby. You'd write something like this:
module Bank class Account end end irb(main):005:0> account = Bank::Account.new => #<Bank::Account:0x0000000106115b00> irb(main):006:0> account.class.name => "Bank::Account" irb(main):008:0> account.class.name.split("::").last => "Account"
In Rails, you can use the
demodulize method on the string, which is added by Active Support. It removes the module part from the constant expression in the string.
irb(main):014:0> account.class.name.demodulize => "Account"
Internally, this method calls the
demodulize class method on the
ActiveSupport::Inflector class, passing itself as the argument.
# File activesupport/lib/active_support/core_ext/string/inflections.rb, line 166 def demodulize ActiveSupport::Inflector.demodulize(self) end
Inflector.demodulize function does the same thing.
demodulize('ActiveSupport::Inflector::Inflections') # => "Inflections" demodulize('Inflections') # => "Inflections" demodulize('::Inflections') # => "Inflections" demodulize('') # => ""
However, its internal implementation is different than our simple version above.
# File activesupport/lib/active_support/inflector/methods.rb, line 228 def demodulize(path) path = path.to_s if i = path.rindex("::") path[(i + 2)..-1] else path end end
After converting the
path argument to a string, it gets the index of the last occurrence of
:: using Ruby's
rindex function. If it exists, then it returns the remaining substring. Otherwise, it returns the original string. The
array[n..-1] expression returns the substring from
n to the last character in the string.
So these are a few ways to get an object's class name in Ruby and Rails. I hope it helped.