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As long as we're (micro)optimizing, ...

I agree, that is a micro-optimisation :), but if you look at the bigger picture, your version is anything from 45% to 350% faster than the List::Util version--it's not so micro.

Plus, your solution inspired me to come up with this, I think, rather surprising version. It's not only faster again, sometimes as much as another 25% over the earlier gains, it's also arguably the most readable:

sub bukNew ($) { my( $ref ) = @_; my @x = 0 .. $#$ref; @{ $ref }[ map splice( @x, rand @x, 1 ), @x ]; } 10 strings length 1.25892541179417 Rate naive listutil blokhead buk bukNew naive 22172/s -- -41% -69% -69% -73% listutil 37867/s 71% -- -47% -47% -54% blokhead 71022/s 220% 88% -- -1% -14% buk 72090/s 225% 90% 2% -- -12% bukNew 82136/s 270% 117% 16% 14% -- 10 strings length 10 Rate naive listutil blokhead buk bukNew naive 20685/s -- -44% -70% -71% -75% listutil 36824/s 78% -- -47% -49% -55% blokhead 70065/s 239% 90% -- -3% -14% buk 72090/s 249% 96% 3% -- -12% bukNew 81717/s 295% 122% 17% 13% -- 10 strings length 1000 Rate naive listutil blokhead buk bukNew naive 1193/s -- -60% -98% -98% -99% listutil 2981/s 150% -- -96% -96% -96% blokhead 69931/s 5764% 2246% -- -2% -15% buk 71723/s 5914% 2306% 3% -- -12% bukNew 81873/s 6765% 2647% 17% 14% -- 100 strings length 1.25892541179417 Rate naive listutil buk blokhead bukNew naive 2190/s -- -45% -72% -73% -78% listutil 3989/s 82% -- -49% -51% -60% buk 7848/s 258% 97% -- -4% -21% blokhead 8144/s 272% 104% 4% -- -18% bukNew 9925/s 353% 149% 26% 22% -- 100 strings length 10 Rate naive listutil buk blokhead bukNew naive 2092/s -- -46% -73% -74% -79% listutil 3868/s 85% -- -50% -52% -61% buk 7811/s 273% 102% -- -4% -21% blokhead 8094/s 287% 109% 4% -- -18% bukNew 9873/s 372% 155% 26% 22% -- 100 strings length 1000 Rate naive listutil buk blokhead bukNew naive 96.3/s -- -58% -99% -99% -99% listutil 229/s 138% -- -97% -97% -98% buk 7811/s 8009% 3314% -- -4% -21% blokhead 8094/s 8303% 3437% 4% -- -18% bukNew 9869/s 10145% 4213% 26% 22% -- 1000 strings length 1.25892541179417 Rate naive listutil buk blokhead bukNew naive 208/s -- -41% -74% -75% -76% listutil 350/s 69% -- -56% -58% -59% buk 789/s 280% 125% -- -5% -7% blokhead 827/s 298% 136% 5% -- -3% bukNew 850/s 310% 143% 8% 3% -- 1000 strings length 10 Rate naive listutil buk blokhead bukNew naive 187/s -- -42% -76% -77% -78% listutil 319/s 71% -- -59% -61% -62% buk 777/s 316% 143% -- -5% -7% blokhead 815/s 337% 155% 5% -- -2% bukNew 834/s 347% 161% 7% 2% -- 1000 strings length 1000 Rate naive listutil buk blokhead bukNew naive 8.47/s -- -62% -99% -99% -99% listutil 22.2/s 162% -- -97% -97% -97% buk 785/s 9164% 3437% -- -3% -8% blokhead 810/s 9470% 3554% 3% -- -5% bukNew 850/s 9939% 3733% 8% 5% --

It's advantage tails off as the number of strings rise, but when you start seeing numbers like 20x, 30x and even 40x faster than the List::Util PP version, it seems possible that someone might benefit.

'sides, I think of optimising as a lot like obfu, a fun intellectual challange. Plus there is the upside that the results can be useful.


Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^3: About List::Util's pure Perl shuffle() by BrowserUk
in thread About List::Util's pure Perl shuffle() by blazar

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