ファイルがソートされていると仮定すると、
sub get {
my ($fh) = @_;
my $line = <$fh>;
return () if !defined($line);
return split(' ', $line);
}
my ($key1, $val1) = get($fh1);
my ($key2, $val2) = get($fh2);
while (defined($key1) && defined($key2)) {
if ($key1 lt $key2) {
print(join("\t", $key1, $val1), "\n");
($key1, $val1) = get($fh1);
}
elsif ($key1 gt $key2) {
print(join("\t", '', '', $key2, $val2), "\n");
($key2, $val2) = get($fh2);
}
else {
print(join("\t", $key1, $val1, $key2, $val2), "\n");
($key1, $val1) = get($fh1);
($key2, $val2) = get($fh2);
}
}
while (defined($key1)) {
print(join("\t", $key1, $val1), "\n");
($key1, $val1) = get($fh1);
}
while (defined($key2)) {
print(join("\t", '', '', $key1, $val1), "\n");
($key2, $val2) = get($fh2);
}