lost - map { "$_:\t$h->{$_}[0]\n"} keys %$h

[Jerry Preston]

Hi!

Can anyone explain to me how map works in this code?

  for my $h (

   # grab the Subject and Date from every message in my (fictional!) smut
folder;
   # the first argument is a reference to an array listing all messages in
the folder
   # (which is what gets returned by the $imap->search("ALL") method when
called in
   # scalar context) and the remaining arguments are the fields to parse out

   # The key is the message number, which in this case we don't care about:
   values %{$imap->parse_headers( scalar($imap->search("ALL")) , "Subject",
"Date")}
  ) {
    # $h is the value of each element in the hash ref returned from
parse_headers,
    # and $h is also a reference to a hash.
    # We'll only print the first occurance of each field because we don't
expect more
    # than one Date: or Subject: line per message.
     print map { "$_:\t$h->{$_}[0]\n"} keys %$h ;
  }

How can I access this and break it done to look at each line?

Thanks,

Jerry