aruprakshit/to_a.md

Last active August 29, 2015 14:03

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Playing with Enumerable#to_a

Raw

Enumerable#to_a says, that it can take arguments also. Lets try

(1..4).to_a(1,2)
#ArgumentError: wrong number of arguments (2 for 0)

Oops! Why then error ? Because Enumerable#to_a called actually Range#each which don't accept any arguments. Now look the below code :-

class Foo
 include Enumerable
 def each(a, b, c)
   yield c
   yield b
   yield a
 end
end

Foo.new.to_a(1, 2, 3)
# => [3, 2, 1]

Now, we can see that Enumerable#to_a takes argument, if the receiver's class implements the #each method to support it.

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