[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] ?
If there are ten directory entries, then $#entries will be 9, and
$#entries+1 will be 10. rand(10) yields 0 <= rand < 10. That truncates
to 0 <= rand <= 9.
--
John W. Kennedy
"...if you had to fall in love with someone who was evil, I can see why
it was her."
-- "Alias"
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