llancet has asked for the wisdom of the Perl Monks concerning the following question: In an recent work, I have to compare two splitted regions, and found the intersection (or substraction, etc) of it. To achieve this, I used string masking system like below: my $region1=[[1,2],[5,7]]; my $region2=[[2,6]]; my $mask1=&toMask($region1); # 1100111 my $mask2=&toMask($region2); # 0111110 my $mask3=&mas