[LON-CAPA-users] List::Util
Seema Ali
sali at vsb.bc.ca
Fri Nov 23 09:53:12 EST 2012
Sorry that was a dumb question. I'm not that much of a Perl programmer.
When I need a shuffle function I use a modified version of:
sub fisher_yates_shuffle {
my $deck = shift; # $deck is a reference to an array
my $i = @$deck;
while ($i--) {
my $j = int rand ($i+1);
@$deck[$i,$j] = @$deck[$j,$i];
}
}
# shuffle my mpeg collection
#
my @mpeg = <audio/*/*.mp3>;
fisher_yates_shuffle( \@mpeg ); # randomize @mpeg in place
print @mpeg;
from: http://perl.active-venture.com/pod/perlfaq4-dataarrays.html
for first, you might try something like:
@blues = qw/azure cerulean teal turquoise lapis-lazuli/;
%is_blue = ();
for (@blues) { $is_blue{$_} = 1 }
I've never used first before so I'm not sure if that'll help or not. The code is found on the same page.
I hope that helps.
>From Seema.
________________________________________
From: lon-capa-users-bounces at mail.lon-capa.org [lon-capa-users-bounces at mail.lon-capa.org] on behalf of Gerd Kortemeyer [korte at lite.msu.edu]
Sent: 23 November 2012 05:20
To: Discussion list for LON-CAPA users
Subject: Re: [LON-CAPA-users] List::Util
Hi,
On Nov 23, 2012, at 7:56 AM, Peter Dencker <dencker at math.uni-luebeck.de> wrote:
>
> Hi, can one use the functions defined in List::Util ?
>
> I tried
>
> <problem>
> <script type="loncapa/perl">
>
> use List::Util qw(first shuffle);
>
> </script>
> </problem>
>
> and this crashed.
"Use" in general is not supported in scripting environment, since many libraries involve and allow I/O.
- Gerd.
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