如何返回数组和hashref？

Question

我想创建一个子程序,将元素(带有值的键)添加到先前定义的散列中.该子例程在循环中调用,因此哈希增长.我不希望返回的哈希覆盖现有元素.

最后,我想输出整个累积的哈希值.

现在它不打印任何东西.最终的哈希看起来是空的,但不应该.我已经尝试了哈希引用,但它并没有真正起作用.在简短的表单中,我的代码如下所示:

sub main{
  my %hash;
  %hash=("hello"=>1); # entry for testing

  my $counter=0;
  while($counter>5){ 
    my(@var, $hash)=analyse($one, $two, \%hash);
    print ref($hash);

    # try to dereference the returning hash reference,
    # but the error msg says: its not an reference ...
    # in my file this is line 82
    %hash=%{$hash};

    $counter++;
  }

  # here trying to print the final hash
  print "hash:", map { "$_ => $hash{$_}\n" } keys %hash;
}

sub analyse{
  my $one=shift;
  my $two=shift;
  my %hash=%{shift @_};
  my @array; # gets filled some where here and will be returned later 

  # adding elements to %hash here as in 
  $hash{"j"} = 2;  #used for testing if it works

  # test here whether the key already exists or
  # otherwise add it to the hash

  return (@array, \%hash);
}

但这根本不起作用:子程序analyse接收散列,但其返回的散列引用为空或我不知道.最后什么都没打印出来.

首先它说,它不是参考,现在它说:

Can't use an undefined value as a HASH reference
    at C:/Users/workspace/Perl_projekt/Extractor.pm line 82.

我的错误在哪里？

我很感谢任何建议.

Answer 1

数组在perl中变平,因此你的hashref会被插入@var.

尝试这样的事情:

my ($array_ref, $hash_ref) = analyze(...)

sub analyze {
  ...
  return (\@array, \@hash);
}