http://qs321.pair.com?node_id=703053


in reply to checking if hashref value exists based on a dynamic array

sub deep_exists {
  my $hash = shift;
  return 0 if @_ == 0;
  while (@_ > 1) {
    $hash = $hash->{shift} or return 0;
  }
  return exists $hash->{$_[0]};
}

if (deep_exists(\%hash, 'a', 't', 'etc')) {
  ...
}

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Re^2: checking if hashref value exists based on a dynamic array
by kyle (Abbot) on Aug 08, 2008 at 15:15 UTC

    Did you try this? Generally, "$hash->{shift}" is interpreted as "$hash->{'shift'}", but I think you mean "$hash->{shift()}".

    Also, this and other solutions I've seen here seem to ignore the possibility of running into a non-hash somewhere along the way. 

    use Test::More 'tests' => 5;

sub deep_exists {
    my $hash = shift;
    my $key = shift;

    return 0 if ( ref $hash ne ref {} || ! exists $hash->{$key} );
    return deep_exists( $hash->{$key}, @_ ) if @_;
    return 1;
}

my %h;
$h{there}{also}{yes} = 1;
$h{hash}{shift}{scalar} = 1;

ok( deep_exists( \%h, 'there', 'also', 'yes' ), 'there also yes' );
ok( deep_exists( \%h, 'there', 'also' ), 'there also' );
ok( ! deep_exists( \%h, 'there', 'also', 'no' ), 'there also no' );
ok( deep_exists( \%h, 'hash', 'shift', 'scalar' ), 'hash shift scalar'
+ );
ok( ! deep_exists( \%h, 'hash', 'shift', 'scalar', 'hash' ),
    'hash shift scalar hash' );

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      Also, this and other solutions I've seen here seem to ignore the possibility of running into a non-hash somewhere along the way

      Mine (Data::Diver) checks.

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