c:\@Work\Perl\monks>perl -wMstrict -le
"my @GI = (
   'gi|Q384722390|emb|WP_938420210.1|Gene name',
   'gi|342546780|emb|WP_934203412.1|Gene name',
   'gi|342546780|emb|WP_93420341211|Gene name',
   'gi|987654321|emb|WP_555555555.1|Jean name',
   );
 ;;
 my @Accession = qw(WP_938420210.1  WP_934203412.1);
 my ($rx_acc) =
   map qr{ $_ }xms,
   join q{|},
   map quotemeta,
   @Accession
   ;
 ;;
 GENE:
 for my $gi (@GI) {
   next GENE unless my ($acc) = $gi =~ m{ \b ($rx_acc) \b }xms;
   print qq{'$acc' in '$gi'};
   }
"
'WP_938420210.1' in 'gi|Q384722390|emb|WP_938420210.1|Gene name'
'WP_934203412.1' in 'gi|342546780|emb|WP_934203412.1|Gene name'

##</code><code>##

my $n = 12;
GENE:
for my $gi (@GI) {
  next GENE unless
    my ($acc) = $gi =~ m{ \A .{$n,}? (?<= [|]) ($rx_acc) (?= [|]) }xmso;
  print qq{'$acc' in '$gi'};
  }