use strict;
use warnings;
use autodie;
use feature 'say';

my $filename = 'rr.txt';
open my $fh,'<',$filename;

while (<$fh>) {
  my ($last_name,$first_name,$country) = split /[,\|]/,$_;
  my $middle_name;
  $country =~ s/^\(//;
  $country =~ s/\)$//;
  say "Last Name: $last_name";
  say "First Name: $first_name";
  say "Country: $country";

  if ($first_name =~ /\w\s(\w+)/) {
     $middle_name = $1;
     say "Middle Name: $1";
  } elsif ($first_name =~ /\w\-(\w+)/) {
     $middle_name = $1;
     say "Middle Name: $1";
  }

}

该文件如下所示：

Reid,Matt|(AUS)
Samper-Montana,Jordi|(ESP)
Krajonovic,Filip|(SRB)
Jones,Greg Luke|(AUS)
Burquier,Gregoire|(FRA)
Mandol,David|(ARG)
Daniel Llosa,Miguel Horpo|(DOM)

每当输出一个中间名时,就会出现换行符.我不知道那是从哪里来的.
使用print和追加换行也会发生同样的事情.