On May 25, Tielman Koekemoer (TNE) said:
Thanks for the help. So I cannot use an array or hash in angle
brackets as file handle. I have a variable amount of files which I'd
like opened and the contents shuffled. What would be the best way to
do this as my next idea also did not work?
@files=`ls /app2/koekemtn/scripts/dbstats/test`;
First of all, you need to chomp() this array, since all its elements end
in newlines. Second of all, you should not be using `ls ...` for this,
because Perl offers you opendir(), readdir(), and closedir(). Or, if
you're a little lazy, glob().
my $dbpath = '/app2/koekemtn/scripts/dbstats/test';
opendir my($dbdir), $dbpath or die "can't readdir $dbpath: $!";
my @dbfiles = readdir $dbdir;
closedir $dbdir;
Now you have all the file *names* in an array. Since they're in another
directory entirely, you'll have to put their path in front of them:
# use this line instead of the readdir() line above
my @dbfiles = map "$dbpath/$_", readdir $dbdir;
Finally, you probably only want files, not directories. Your `ls ...`
code didn't discriminate, but readdir() returns ALL entries, including '.'
and '..', so we do have to be specific:
# use this
my @dbfiles = grep -f, map "$dbpath/$_", readdir $dbdir;
(At this point, if you don't understand anything I've coded, I'd suggest
you look at 'perldoc -f opendir', 'perldoc -f readdir', 'perldoc -f
closedir', 'perldoc -f map', 'perldoc -f grep', and 'perldoc -f -X'. Or
you could ask more here, but it would help those of us that answer
questions a great deal if you read the docs first.)
$num =1;
foreach $line ( @files ) {
chomp $line;
Eh, you chomp() now. But I wouldn't have used `ls ...`.
open ( $line , "$line") || die "Cannot open $files[0]\n";
You've got $files[0] there, but you're not always using $files[0], you're
using $line. You also didn't include $! in your error message, which
would tell you WHY it couldn't open the file.
$file$num = $line; # Problem assignment!
Whenever you see that you have a group of variables called $this_1,
$this_2, $this_3, etc., it's a sign that you should be using an array. In
fact, you already HAVE the array (@files) since you're using the elements
of the array both as paths to files AND as the filehandles themselves.
It's a little unorthodox, but it's not a crime. I wouldn't do it, though,
I'd create filehandles:
my @fh;
for (@dbfiles) {
open my($f), "< $_" or die "can't read $_: $!";
push @fh, $f;
}
Now for every element in @dbfiles, the matching element in @fh is a
filehandle for it.
--
Jeff "japhy" Pinyan % How can we ever be the sold short or
RPI Acacia Brother #734 % the cheated, we who for every service
http://japhy.perlmonk.org/ % have long ago been overpaid?
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