[EMAIL PROTECTED] wrote:
> "John W. Kennedy" <[EMAIL PROTECTED]>
> 07/29/2005 04:13 PM
>
> To
> [EMAIL PROTECTED]
> cc
> [email protected]
> Subject
> Re: randomly choosing a file
>
>
>
>
>
>
> [EMAIL PROTECTED] wrote:
>
>>I know how to and can successfully open a directory , but i need to
>
> choose
>
>>a file within the directory at random to verify the data on. does anyone
>
>
>>have any suggestions of how to do this? i'm thinking it could take a
>
> while
>
>>to create an array of the file names and then randomly pick a slot
>
> there,
>
>>but that;s all i can think of right now.
>
>
>
>
> Unfortunately, this is not likely to do you any good, because you need
> to know the value of n before starting, and the correct value can be
> obtained only by reading the directory in the first place. So....
>
> my @entries;
> opendir MYDIR, $directory;
> while (my $entry = readdir MYDIR) {
> next if -d "$directory/$entry";
> push @entries, $entry;
> }
> closedir MYDIR;
>
> my $chosenfile = @entries[int rand ($#entries + 1)];
>
>
> this looks like a more efficient variation upon what i was thinking. i
> have one question though.. the array starts at 0 for an index, doesn't
> $#var give one less than the element in the array since it uses the last
> index in the array? wouldn't this mean one wants to *1 to make an integer
> instead of +1 and make the result 1 to [one-greater-than-array] ?
I avoid $# most of the time since I seldom need it.
use strict;
use warnings;
my $dir = './txt';
opendir DIR, $dir;
my @entries = grep { ! -d "$dir/$_" } readdir DIR;
closedir DIR;
# print name and m of n entries
my $ii = int rand @entries;
print "$dir/$entries[$ii] - $ii of ", scalar @entries, "\n";
__END__
> i figure since there seems to be many people interested in this, that
> potential issue should be brought up here so everyone corrects it if there
> is a mistake. since it is close to what i was thinking it's the type of
> code i would write so I'm going to assimilate some things from that to
> improve my efficiency =o)
>
> i cant use the other suggestion because the script its to test a new
> version of RAIDCORE being used and needs to be alternating to some degree
> between read and writes, the reads are supposed to use a verification
> script we already have. we're playing with mirroring/transforming R5
> arrays.
--
,-/- __ _ _ $Bill Luebkert Mailto:[EMAIL PROTECTED]
(_/ / ) // // DBE Collectibles Mailto:[EMAIL PROTECTED]
/ ) /--< o // // Castle of Medieval Myth & Magic http://www.todbe.com/
-/-' /___/_<_</_</_ http://dbecoll.tripod.com/ (My Perl/Lakers stuff)
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