in reply to How to create hash out of an array elements?

The map callback never gets called since you didn't pass any list to transform, so map returns nothing.

You could create the desired list of two elements as follows:

my %sizes = ( $symbolsizes[0] => $symbolsizes[1] );

But really, all you need is the following:

my %sizes = @symbolsizes;

PS — The language is called "Perl", not "PERL".