Question

I have a long string containing a bibliography, alternating between lines of paper-title/comma-separated-author-list, like the following:

Learning Programs: A Bayesian Approach
P. Liang, M. Jordan, D. Klein
Variational methods for a Dirichelet process
D. Blei, M. Jordan

What I want is a list of unique authors (alphabetized by last name) and counts. In the above example it would be:

D. Blei (1)
M. Jordan (2)
D. Klein (1)
P. Liang (1)

Can anyone tell me how to do this in Perl or visual basic? Thanks so much — you rock!!!

Answer 1

In perl, what you’ll need to do is read through the input, making every other line the author line:

my %list;
while (<DATA>) {
    chomp;
    my $book = $_;
    chomp(my $authors = <DATA>);
    map { push @{$list{$_}}, $book } split /,\s*/, $authors;
}

for (sort { sortA($a) cmp sortA($b) } keys %list) {
    printf "$_ (%s)\n", scalar @{$list{$_}};
}

sub sortA {
     if ($_[0] =~ / (\w+)/) {
        return $1;
    }
 }

__DATA__
Learning Programs: A Bayesian Approach
P. Liang, M. Jordan, D. Klein
Variational methods for a Dirichelet process
D. Blei, M. Jordan