Question

Say I want sort a hash of arrays (%hash) by looking up the comparisons in another hash (%comparator):

I thought the following would work, but it didn’t.

for ($bin_ix=1; $bin_ix<scalar(keys(%cluster_bins)); $bin_ix++) {    
   $hash{$bin_ix} = sort {$comparator{$a} <=> $comparator{$b} $hash{$bin_ix}};
} 

It complains with: Missing operator before %hash. What am I missing?

Answer 1

Actually, it says

Scalar found where operator expected at -e line 2, near "} $hash"
        (Missing operator before  $hash?)

It’s complaining about your misplaced }, but there’s a second problem: $hash{$bin_ix} is merely a reference to the array, not an array. You want

@{ $hash{$bin_ix} } =
   sort { $comparator{$a} <=> $comparator{$b} }
      @{ $hash{$bin_ix} };