use strict; use warnings; # Set up arrays, use hash to find elements of # @arrB not duplicated in @arrA. # my @arrA = (1, 2, 3, 4); my @arrB = (1, 5, 3, 6, 8, 2, 4); my %hashA; @hashA{@arrA} = (); my @nonDup = grep { not exists $hashA{$_} } @arrB; # Show arrays. # print qq{Before\n}, qq{@arrA\n}, qq{@arrB\n}, qq{@nonDup\n}; # Look to replace value 3 in @arrA. Loop over @arrA # to find the element we want. # my $toReplace = 3; foreach my $idx ( 0 .. $#arrA ) { next unless $arrA[$idx] == $toReplace; # Use splice to take the found element out of # @arrA and replace it with one randomly splice'ed # out of @nonDup. # splice @arrA, $idx, 1, splice @nonDup, int rand @nonDup, 1; last; } # Show what we have now. # print qq{After\n}, qq{@arrA\n}, qq{@arrB\n}, qq{@nonDup\n};