my $str = qq(<data><tuple name="Abb">ARG</tuple><tuple name="Reg">EU</tuple></data> 
<data><tuple name="Abb">ARG</tuple><tuple name="Reg">a_neh_2-vf-4nm</tuple></data> 
<data><tuple name="Abb">ARG</tuple><tuple name="Reg">a_neh_2-vf-4nm</tuple></data> 
<data><tuple name="Abb">ARG</tuple><tuple name="Reg">HGYIuy 6798</tuple></data>);  
 
# There's probably a better way but you can try these. 
# Providing your values don't contain '<', 
 
# to create an array you could...  
 
my @vals; 
$str =~ s/name="Reg">([^<]*)</push@vals,$1/eg; 
print "$_\n" for @vals;  
 
# Or to create a hash you could...  
 
my %h; 
my $name = 1; 
$str =~ s/name="Reg">([^<]*)</$h{$name++}=$1/eg; 
print "$h{$_}\n" foreach keys %h;