On 5/9/10 Sun May 9, 2010 1:02 PM, "Harry Putnam" <rea...@newsguy.com>
scribbled:
> Shawn H Corey <shawnhco...@gmail.com> writes:
>
>
>> my %inv_hash = invert( \%hash );
>> print '%inv_hash: ', Dumper \%inv_hash;
>>
>> This will output:
>>
>> %inv_hash: $VAR1 = {
>> 'f2' => [
>> './b/l/c/f2'
>> ],
>> 'fb' => [
>> './b/fb',
>> './b/g/h/r/fb'
>> ],
>> 'fc' => [
>> './b/g/f/r/fc'
>> ],
>> 'fd' => [
>> './b/c/fd'
>> ]
>> };
>>
>> Note that both values for fb are preserved.
>
> I hadn't caught that. But that is really nifty.
>
> If its not to much to ask, how would one get at both of those?
Let $inverted_key have a value from the original hash (e.g., 'fb'). Then the
keys of the original hash that have a value of 'fb' can be fetched into an
array with the following (untested):
my @original_keys = @{$inv_hash{$inverted_key}};
The element of the inverted hash is an array reference. The array is fetched
(copied into @original_keys) by de-referencing the reference. If there was
only key with the value $invereted_key, then the array @original_keys will
have only one element.
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