How can get Ruby to tell me when I'm overwriting an existing key in my
hash?
For example,
h = { "key1" => [6, 44, 12],
"key2" => [8, 1],
.
.
}
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.
Well, if you always have arrays for the values, you can start with:
h = Hash.new {|h,k| h[k] = }
Then initialize your hash with:
h.update({ "key1" => [6, 44, 12],
"key2" => [8, 1],
...
})
Then you can:
h["key1"] << 99 << 3
h["key1"].concat([99, 3])
h["key1"].push(99, 3)
h["key1"] has [6,44,12,99,3]
-Rob
Rob Biedenharn http://agileconsultingllc.com
Rob@AgileConsultingLLC.com
On Sep 19, 2008, at 6:37 PM, jim wrote:
How can get Ruby to tell me when I'm overwriting an existing key in my
hash?For example,
h = { "key1" => [6, 44, 12],
"key2" => [8, 1],
.
}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.
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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