I am not sure I understand what you require, but if it is "How might I sort the keys or values of a hash by the index in the  @cols array of the value of the hash element", then it is necessary to first make a mapping of the elements of the  @cols array to their indices: another hash.

Once you have the element-to-index mapping of the array, it is straightforward to sort the keys or values of the original hash by these indices. 

>perl -wMstrict -le
"my @cols = qw(bar wobble mosh hop);
 my %hash = (
   wibble => $cols[1],
   foo    => $cols[0],
   hip    => $cols[3],
   mish   => $cols[2],
   );
 my %i_map = map { $cols[$_] => $_ } 0 .. $#cols;
 print
   join ' ',
   qq{keys sorted by \@cols index of value: \n},
   sort { $i_map{ $hash{$a} } <=> $i_map{ $hash{$b} } }
   keys %hash
   ;
 print
   join ' ',
   qq{values sorted by \@cols index of value: \n},
   sort   { $i_map{$a} <=> $i_map{$b} }
   values %hash
   ;
"
keys sorted by @cols index of value:
 foo wibble mish hip
values sorted by @cols index of value:
 bar wobble mosh hop

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The preceding assumes that every value of the hash is an element of the array; it would be wise to validate this assumption.

In reply to Re: sorting hashes by AnomalousMonk
in thread sorting hashes by Angharad

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