From: Hal Fulton <hal9000@...>
Date: 2004-01-28T01:34:36+09:00
Subject: Re: newbee question about "missing" hash methods +, += and <<

ts wrote:
>>>>>>"b" == benny  <linux@marcrenearns.de> writes:
> 
> b> thats the behaviour of arrays and I know that I could extend the class
> b> Hash, so that its supported. I simply want to know if there is a special
> b> reason why it is not supported by default. 
> 
>  What do you do if the key exist ?
> 
>  Array#+ always add elements, with Hash#+ keys will be added only if the
>  key don't exist otherwise the old value is replaced.

I have seen this discussion before.

It doesn't bother me much that keys are replaced. That is the nature of
a Hash, that keys are unique.

What bothers me more: If h2 and h3 have common keys, then
    h1 = h2 + h3
is not the same as
    h1 = h3 + h2

In other words, I expect + to be commutative always. But probably
someone will now show me a case where it is not in Ruby.  :)


Hal