build_new_array=>q[
        my @a = 1 .. $N;
        my @b;
        for (@a) {
            push @b, $_ if /9/;
        }
    ],

##</code><code>##

    edit_in_place=>q[
        my @a = 1 .. $N;
        my $o = 0;
        for (@a) {
            $a[$o++]=$_ if /9/;
        }
        $#a=$o-1;
    ],

##</code><code>##

$ for J in 2 3 4 5 6; do perl 1036631.pl -N=1e$J; done

                Rate offset_copy        grep for_splice  build_new edit_in_place
offset_copy   3288/s          --        -10%       -27%       -37%          -38%
grep          3657/s         11%          --       -18%       -30%          -31%
for_splice    4483/s         36%         23%         --       -14%          -16%
build_new     5191/s         58%         42%        16%         --           -3%
edit_in_place 5338/s         62%         46%        19%         3%            --

               Rate offset_copy        grep for_splice   build_new edit_in_place
offset_copy   319/s          --        -14%       -22%        -37%          -40%
grep          369/s         16%          --       -10%        -27%          -30%
for_splice    411/s         29%         11%         --        -19%          -22%
build_new     505/s         58%         37%        23%          --           -5%
edit_in_place 528/s         66%         43%        29%          5%            --

                Rate for_splice offset_copy        grep  build_new edit_in_place
for_splice    28.6/s         --         -3%         -8%       -35%          -42%
offset_copy   29.4/s         3%          --         -5%       -33%          -40%
grep          31.1/s         9%          6%          --       -29%          -37%
build_new     43.8/s        53%         49%         41%         --          -11%
edit_in_place 49.1/s        72%         67%         58%        12%            --

            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
                 Rate for_splice offset_copy       grep  build_new edit_in_place
for_splice    0.433/s         --        -86%       -87%       -90%          -90%
offset_copy    3.00/s       593%          --       -11%       -28%          -34%
grep           3.36/s       676%         12%         --       -19%          -26%
build_new      4.17/s       862%         39%        24%         --           -8%
edit_in_place  4.55/s       950%         52%        35%         9%            --

            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
              s/iter for_splice offset_copy        grep  build_new edit_in_place
for_splice       632         --        -99%       -100%      -100%         -100%
offset_copy     3.38     18587%          --        -18%       -28%          -36%
grep            2.76     22785%         22%          --       -12%          -22%
build_new       2.43     25893%         39%         14%         --          -11%
edit_in_place   2.16     29142%         56%         28%        13%            --