On Tue, Jul 31, 2001 at 06:32:15PM -0500, CDitty wrote:
: In both my perl books. Learning Perl(O'Reilly) and Perl 5 Interactive
: Course(Waite Group).
:
: The shuffle routine in not listed in either of these books, although they
: are almost 1 year old. When I try and use shuffle I get
: Undefined subroutine &main::shuffle and my program stops.
Did you read the documentation provided by executing 'perldoc -q
shuffle'?
If you did, you noticed a subroutine in the coding example that
shuffles an array with the fisher-yates algorithm. I'll post it here
so everyone can see it
Use this:
# fisher_yates_shuffle( \@array ) :
# generate a random permutation of @array in place
sub fisher_yates_shuffle {
my $array = shift;
my $i;
for ($i = @$array; --$i; ) {
my $j = int rand ($i+1);
next if $i == $j;
@$array[$i,$j] = @$array[$j,$i];
}
}
fisher_yates_shuffle( \@array ); # permutes @array in place
There is another example in that FAQ question which was posted here by
Micheal Fowler, whose name I surely misspelled. :-)
Casey West
--
Shooting yourself in the foot with Fortran
You shoot yourself in each toe, iteratively, until you run out of
toes; then you shoot the sixth bullet anyway since no exception
processing was anticipated.
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
