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I was thinking about that "one line" of code... and wondering if it was really a good shuffle. I'm not convinced that it is a better shuffle then Fisher-Yate's, since it doesn't seem to allow anything to stay in its original location. It also occured to me that calling QuickSort with a random requirement like that would take awhile. So I ran a benchmark.
DB<4> sub Shuffle{my $ar=shift; my $i=@$ar; while($i--){my $n=int ra +nd(1+$i); @$ar[$i,$n]=@$ar[$n,$i]}} DB<5> @a = ( 0..9999 ) DB<6> timethese( 1000, { FY => 'Shuffle(\@a)', SR => '@a=sort{(-1,1) +[rand 2]}@a' }) Benchmark: timing 1000 iterations of FY, SR... FY: 63 wallclock secs (61.93 usr + 0.00 sys = 61.93 CPU) @ 16 +.15/s (n=1 000) SR: 157 wallclock secs (155.34 usr + 0.00 sys = 155.34 CPU) @ + 6.44/s ( n=1000)
Which I read to say Fisher-Yates is almost three times faster then the one-liner.

In reply to Re: Randomize an array by Adam
in thread Randomize an array by Zebu

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