Tuesday, September 10, 2013
On Tuesday, September 10, 2013 8:27:13 AM UTC+1, tamouse wrote:
> I do know that Hash don't allow duplicate keys. But I would like to by
> which method hash check if any duplicate key present into it or not? As
> I can see "foo" have different `object_id`,which is expected. But in
> case of Hash key how this two different objects "foo" is treated as same
> object?
The hash's keys' object id's are not what is compared. If you take both of those strings, and did this:
"foo" == "foo"
You'd get true, regardless of the fact they have different object ids.
You are making this way way way more complicated than it is.
By default yes, eql? is used for hash keys (and eql? in turn generally calls ==).
You can ask for a hash to use object identity though:
h = {}.compare_by_identity => {}
h['a'] = 1 # => 1
h['a'] = 2 # => 2
h # => {"a"=>1, "a"=>2}
Although it's not something I've ever needed or seen in the wild.
Fred
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