From: SpringFlowers AutumnMoon <summercoolness@...>
Date: 2007-09-18T18:30:18+09:00
Subject: Re: how to use tuple as hash key

Stefano Crocco wrote:
>
> insert the line
> 
>   h2.rehash
> 
> after
> 
>   h2[a] = "ha"
> 
> you'll get the expected behaviour.

actually if the code is

for i in 1..2
  for j in 1..2
    a[0] = i
    a[1] = j
    h2[a] = "ha"
    h2.rehash
  end
end

p h2

it will print out:

{[2, 2]=>"ha"}

=========================
if i use

h2 = {}
a = [0, 0]

for i in 1..2
  for j in 1..2
    a[0] = i
    a[1] = j
    h2[a.dup] = "ha"
  end
end

p h2

then it will print out

{[1, 2]=>"ha", [2, 1]=>"ha", [1, 1]=>"ha", [2, 2]=>"ha"}


but my question is, if i run the loop 10 million times (for some 
statistics), then it will actually duplicate the array 10 million times, 
which is memory hungry.  so i wonder what is a better way.  if a is just 
a list of numbers, i can certainly use  a.join(",") as the key... but 
looping 10 million times will also create "frozen strings" in the hash 
table 10 million times too?



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