As has been suggested before, please read Writeup Formatting Tips. In particular, you should be using <code> tags to preserve whitespace and <p> to break paragraphs.

This is a fairly straightforward task using hashes. First iterate over your first list and increment the value on that key, i.e. 

my %hash = ();
foreach my $element (@list1) {
    $hash{$element}++;
}

[download]

Repeat for the second list, and voila, if a key has a value of 2, it's in both lists. Post some code, and then we can help you debug it.

Update: Or if you don't want to write any code, you could always use List::Compare::Functional.

In reply to Re: how to convert two lists into adjacency matrix by kennethk
in thread how to convert two lists into adjacency matrix by koleti

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