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perlperl-data-structures

Convert string "a.b.c" to $hash->{a}->{b}->{c} in Perl

I've dynamic nested hash-refs like this:

my $hash = { 'a' => { 'b' => { 'c' => 'value' } } };

I want to set the value of c to 'something' by allowing the user to input "a.b.c something".

Now getting the value could be done like this:

my $keys = 'a.b.c'; 
my $v='something';
my $h = $hash;
foreach my $k(split /\./, $keys) {
  $h = $h->{$k};
}
print $h; # "value"

But how would I set the value of key c to $v so that

print Dumper $hash;

would reflect the change? $h is not a ref at the end of the foreach loop, so changing that won't reflect the change in $hash. Any hints how to solve the knots in my head?

Solution

  • Something like this:

    my $h = $hash;
my @split_key = split /\./, $keys;
my $last_key = pop @split_key;
foreach my $k (@split_key) {
    $h = $h->{$k};
}
$h->{$last_key} = $v;