From: Siep Korteling <s.korteling@...>
Date: 2008-09-20T08:19:00+09:00
Subject: Re: overwriting hash key

jim wrote:
(...)
> 
> The hash could get big enough where I accidentally add a new entry,
> 
>          "key1" => [99, 3]
> 
> when what I needed to do was add [99, 3] to key1's array. I won't get
> any warning that the first occurrence of key1 is being replaced.

Here you go:

class SafeHash <Hash
 def []=(k,v)
  if self.keys.include?(k) then
    print "Are you really, sure you want to overwrite #{k.to_s}? (Y/N)"
    STDOUT.flush
    super(k,v) if gets.chomp.downcase == "y"
  else
     super(k,v)
  end
 end
end

h = SafeHash.new
h["key1"] = [99,3]
h["key1"] = [12,4]
p h

Regards,

Siep
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