use strict;
use warnings;

my @arr1 = (
    ['a','b','c'],
    ['d','e','f'],
    ['g','h','i'] );
my @arr2 = (
    ['j','k','l'],
    ['m','n','o','p'],
    ['q','r'] );

#1 iterate using map and join
print map {(join ',',@{$arr1[$_]},@{$arr2[$_]})."\n"} 0..$#arr1;

#2 itarting modifying list separator
{ # scope to limit the effect of next statement
  local $"=','; # $LIST_SEPARATOR
  print map {"@{$arr1[$_]},@{$arr2[$_]}\n"} 0..$#arr1;
}

#3 or consuming arrays
while (my $one = shift @arr1 and my $two = shift @arr2){
  print +(join ',',@{$one},@{$two})."\n"
}
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