#!/usr/bin/perl -w

    use strict;

    my @array = ([1], [2], [3], [4], [5]);
    my %skip  = (3 => 1);

    my @keep  = grep {not exists $skip{$_->[0]}} @array;
    my @skip  = grep {    exists $skip{$_->[0]}} @array;

    my @new   = (@keep, @skip);