in reply to compare 2 arrays of strings and form a table
For the output, the first column should be things that don't appear in array2, and each subsequent column should be the values that follow the values in the previous column. If so, you want to reverse football and tennis in your example.
I found it made the most sense to work with hashes so I could model the "follows" relationship.
#!perl use strict; use warnings; my @array1 = qw(read eat book apple play football novel); my @array2 = qw(book apple novel banana football tennis magazine); # The follows relationship my %follow; @follow{@array1} = @array2; # Keeping track of what followers I have already used my %h2 = map {$_=>1} @array2; # Start with things that are not followers my @out = ([grep !exists $h2{$_}, @array1]); # Put followers of the previous column on as a new column while (%h2) { push @out, [@follow{@{$out[-1]}}]; delete @h2{@{$out[-1]}}; } use Data::Dumper; print Dumper(\@out); END { use Data::Dumper; print Dumper(\@out); }
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