How do I access an array in an array of hash in perl?

Question

I have an array of hash that one of the value of hash is an array . -> I push "@title" to "part" and for print , -> I put each of books{part} in a temporary array to access each element of title but it just print the first element I can't access all element of "title" in array "books"

@books = ();
@title = (1,2,3,4,5);
push @books,{subject=>"hello" , part =>@title };
for($i=0;$i<scalar(@books);++$i)
{
    print $books[$i]{subject};

    @temp = $books[$i]{part};
    for($j=0;$j<scalar(@temp);++$j)
    {
        print $temp[$j]; #this print just first element "1"
    }
}

See also: How do I store an array as a value in a Perl hash?. — Grant McLean
– Grant McLean, Commented Aug 1, 2016 at 23:09
there is another problem:for each book it print the information of last book — Mina Shaigan
– Mina Shaigan, Commented Aug 4, 2016 at 11:49

ikegami · Accepted Answer · 2016-08-02 01:26:21Z

4

The problem here is that the Hash reference you are pushing on the @books array is not be created correctly.

The Hash reference you are creating looks like this:

 {  'subject' => 'hello',
    'part'    => 1,
    '2'       => 3,
    '4'       => 5,
 }

when you probably expected it to look like this:

{  'subject' => 'hello',
   'part' => [
        1,
        2,
        3,
        4,
        5,
    ],
}

This is happening because values in Hashes and Arrays have to be SCALAR values. To create the Hash reference correctly to need to store a reference to the @title Array under the key part, you create a reference with a \:

push @books, { subject => "hello", part => \@title };

Note: This also means that when you want to extract the part key into the @temp Array you need to de-reference it (since it is an Array reference):

@temp = @{ $books[$i]{part} };

edited Aug 2, 2016 at 1:26

ikegami

391k17 gold badges291 silver badges555 bronze badges

answered Aug 1, 2016 at 23:01

Hunter McMillen

61.8k25 gold badges124 silver badges176 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How do I access an array in an array of hash in perl?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related