Depending on how big the list is, this might be more efficient than shuffling the whole list for a small number of picks: 

my @a = 4..20;;
my @s = map splice( @a, rand( @a ), 1 ), 1 .. 8;;

print "@a\n@s";;
4 5 7 8 9 12 13 14 18
11 10 6 20 15 17 19 16

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In reply to Re: getting random number 8 times never the same by BrowserUk
in thread getting random number 8 times never the same by Anonymous Monk

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