Using each_with_object or inject with a hash object

Hello,

I'm trying to use each_with_object with a hash initialized using the
Hash.new syntax with an implicit block.
I'm expecting an empty array to be initialized whenever I attempt to access
a new key but my results are a bit different. I looked at the Enumerable
documentation but could not find an answer.

It'll be great if someone can shed some light on what is going on.

Here's the code:

ary = Array.new(10) { [rand(100), rand(100)] }
memo = Hash.new { Array.new }


ary.inject(memo) { |hsh,(i,j)| hsh[i] << j; hsh }

>> {}


ary.each_with_object(memo) { |(i,j),hsh| hsh[i] << j }

>> {}


ary.inject({}) { |hsh,(i,j)| hsh[i] ||= []; hsh[i] << j ; hsh }

>> {k: [v1, v2]}


ary.each_with_object({}) { |(i,j),hsh| hsh[i] ||= []; hsh[i] << j }
>> {k: [v1, v2]}


Thanks,
Adi


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