Hmm.. Redefining makes a significant difference. That is odd, I didn't beleive that any of those functions where modifying the list. Which one is modifying the list?

C:\test>perl 429768.pl
            (warning: too few iterations for a reliable count)
              Rate   Grep Grep + Map   Hash   Map Router Trinary Origi
+nal Switch
Grep        9699/s     --       -36%   -39%  -42%   -44%    -47%     -
+52%   -65%
Grep + Map 15244/s    57%         --    -5%   -9%   -12%    -17%     -
+24%   -45%
Hash       16000/s    65%         5%     --   -5%    -8%    -12%     -
+20%   -43%
Map        16835/s    74%        10%     5%    --    -3%     -8%     -
+16%   -40%
Router     17301/s    78%        13%     8%    3%     --     -5%     -
+13%   -38%
Trinary    18282/s    88%        20%    14%    9%     6%      --      
+-9%   -34%
Original   20000/s   106%        31%    25%   19%    16%      9%      
+ --   -28%
Switch     27855/s   187%        83%    74%   65%    61%     52%      
+39%     --

C:\test>perl 429768.pl
              Rate   Grep Grep + Map    Map  Hash Router Trinary Origi
+nal Switch
Grep        9625/s     --       -38%   -41%  -41%   -45%    -47%     -
+53%   -66%
Grep + Map 15420/s    60%         --    -5%   -5%   -12%    -16%     -
+25%   -46%
Map        16194/s    68%         5%     --   -0%    -8%    -11%     -
+22%   -43%
Hash       16194/s    68%         5%     0%    --    -8%    -11%     -
+22%   -43%
Router     17544/s    82%        14%     8%    8%     --     -4%     -
+15%   -38%
Trinary    18282/s    90%        19%    13%   13%     4%      --     -
+11%   -36%
Original   20640/s   114%        34%    27%   27%    18%     13%      
+ --   -27%
Switch     28450/s   196%        84%    76%   76%    62%     56%      
+38%     --
[download]

Not sure - I'll check though.

Here's my results - I have what you have, but no Grep + Map, and Switch is now Substr Hash (more flexible), plus added the suggestion for split (slightly modified).




           Rate   Eval   Grep    Map REHash SplHash Router   REEq   Or
+ig SubHash
Eval     5522/s     --   -35%   -52%   -54%    -55%   -58%   -58%   -6
+2%    -72%
Grep     8432/s    53%     --   -26%   -30%    -32%   -35%   -36%   -4
+2%    -58%
Map     11468/s   108%    36%     --    -5%     -8%   -12%   -13%   -2
+1%    -42%
REHash  12092/s   119%    43%     5%     --     -3%    -7%    -8%   -1
+6%    -39%
SplHash 12407/s   125%    47%     8%     3%      --    -5%    -6%   -1
+4%    -38%
Router  13055/s   136%    55%    14%     8%      5%     --    -1%   -1
+0%    -34%
REEq    13210/s   139%    57%    15%     9%      6%     1%     --    -
+8%    -34%
Orig    14430/s   161%    71%    26%    19%     16%    11%     9%     
+--    -27%
SubHash 19881/s   260%   136%    73%    64%     60%    52%    50%    3
+8%      --
[download]