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Mastering Modern Perl: Writing Efficient and Maintainable Code

Solution Review: Reverse a Hash

Understand how to reverse a hash in Perl by following a step-by-step explanation. Learn to traverse a hash with loops, swap keys and values, and print the resulting inverted hash. This lesson reinforces fundamental Perl data structure operations and practical coding techniques.

We'll cover the following...

Solution

Let’s look at the solution before jumping into the explanation:

Perl
# Assume that %straight is already defined
my %inverted;
foreach my $k (keys %straight) {
      $inverted{$straight{$k}} = $k;
}
 
#loop for printing the inverted hash
foreach my $element (sort keys %inverted) {
   say "$element => '$inverted{$element}'";
}
...