Re: Dynamically creating a hash for keys()

"reverse" returns a list, not a hash; "keys" expects to see something 
that starts with %.  So you could do this to actually dereference an 
anonymous hash (your version didn't actually make an anonymous hash):

   print keys %{ { reverse %hash } };

Of course you could have just done:

   print values %hash;

(but of course non-unique values would be printed twice).

-Aaron

On Oct 19, 2004, at 9:50 AM, Jason Foster wrote:

> Can anyone help me to understand why this code refuses to compile?  
> Even better, can anyone help fix it :)
>
>     %hash = qw( fred filntstone barney rubble tom delong );
>     print( keys( reverse( %hash ) ) );
>
> The error message...
>
>     Type of arg 1 to keys must be hash (not reverse) at ./killme.pl 
> line 4, near ") ) "
>
> ... was pretty confusing since it implies that "reverse" is a type?!
>
> I tried making an anonymous hash as follows...
>
>     print( keys( %{ reverse( %hash ) } ) );
>
> ... but got no results at all.
>
> Help!
>
>
--
Aaron J. Mackey, Ph.D.
Dept. of Biology, Goddard 212
University of Pennsylvania       email:  [email protected]
415 S. University Avenue         office: 215-898-1205
Philadelphia, PA  19104-6017     fax:    215-746-6697