filehandle
for quite a long time i'm looking for a way to do this...
that's the situation:
i have a file with a list of filenames in it (each line: one name). now i open the file and put the content in an @ (i.e. @articlelist), and close the file.
next: i'd like to open each file in @articlelist and read the content in an own @ (i.e. @article1, @article2, ...), but i'd like to open the files dynamically (foreach $line (@articlelist) {...}) and create the @ dynamically, instead of defining every @article. are you with me?
that's what i have:
### read articlelist into array @articleslist ###
open(ARTICLELIST, "$stuffdirectory/$articlelist") || die "No such file: $articlelist";
@articleslist = <ARTICLELIST>;
close(ARTICLELIST);
### read files, based on @articleslist, into different @
foreach $line (@articleslist) {
open(ARTICLE, "$stuffdirectory/$line") || die "No such file: $line";
### now it's getting difficult: how to create an own @, instead of overwriting the last @?
@articles = <ARTICLE>;
close(ARTICLE);
}thanks for any advise!
Vorm posted this at 20:25 — 30th October 2000.
They have: 62 posts
Joined: May 2000
I'd do all your actions in that foreach. For example:
foreach $line (@articleslist) {
open(HEH, "<$line");
@articles=<HEH>;
close(HEH);
print @articles;
}
But if you insist on creating an array for each one, maybe this:
$i="1";
foreach $line (@articleslist) {
open(HEH, "<$line");
@articles$i=<HEH>;
close(HEH);
++$i;
print @articles;
}
Hope I helped.
merlin posted this at 06:39 — 31st October 2000.
They have: 410 posts
Joined: Oct 1999
thanks vorm, you just gave me a nice idea... i think i'll go for two... but still i'll try one too (just for fun)...
Mark Hensler posted this at 06:48 — 31st October 2000.
He has: 4,048 posts
Joined: Aug 2000
Vorm-
you forgot one little thing. in your second one (I'm assuming you copied and pasted from the first) you forgot the $i at the end of @articles
$i="1";
foreach $line (@articleslist) {
open(HEH, "<$line");
@articles$i=<HEH>;
close(HEH);
print @articles$i;
++$i;
}
Mark Hensler
If there is no answer on Google, then there is no question.
merlin posted this at 07:08 — 31st October 2000.
They have: 410 posts
Joined: Oct 1999
well, i have that, but i get a syntax-error...
here's my code:
$i = "1";foreach $line (@articleslist) {
open(ARTICLE, "$stuffdirectory/$line") || die "No such file: $line";
@articles$i = <ARTICLE>;
close(ARTICLE);
++$i;
}
the error is in line 5 (@articles$i =
japhy posted this at 21:47 — 31st October 2000.
They have: 161 posts
Joined: Dec 1999
That's because $foo$bar = "something" is not valid syntax in Perl. What you're trying to do is:
@{"articles$i"} = (...);That's called a "soft reference". DO NOT USE THEM. They have one very specific use in Perl, and that is the only time they should be used. Specifically, their use is NOT in this case. You should probably be using an array of references to arrays:
for (@lines) {my @words = split;
# push @list_of_words = \@words; # <-- ERROR
}
Now @list_of_words is an array, each of whose elements are references to an array. To access the data, you'd do something like:
for (@list_of_words) {my @data = @$_; # @{ ... } dereferences an array ref
# ...
}
For more information on references, read the perlreftut, perlref, perldsc, and perllol documentation (available on your computer or at http://www.perldoc.com/. I also have a small document on using references on my web site at http://www.pobox.com/~japhy/.
UPDATE: check my next post for the correction of that code. Silly japhy...
[Edited by japhy on 10-31-2000 at 08:16 PM]
Vorm posted this at 00:59 — 1st November 2000.
They have: 62 posts
Joined: May 2000
Your PERL is weird looking japhy.
Anyways, I'd just do the processes for each array without creating one for each file.
japhy posted this at 01:15 — 1st November 2000.
They have: 161 posts
Joined: Dec 1999
So is your spelling of "Perl", Vorm.
What strikes you as odd about my Perl code? The fact that I didn't send any arguments to split()? The fact that I used the default $_ variable in my for loops?
Err, the fact that I called push incorrectly... that should have been
for (@lines) {my @words = split;
push @list_of_words, \@words;
}
There. Less odd-looking now?
japhy posted this at 01:19 — 1st November 2000.
They have: 161 posts
Joined: Dec 1999
Anyway, there probably is no need to store all the lines of the file into an array, and then iterate over the array. That takes up memory needlessly. Use a while loop.
open FILE, $filename or die "can't read $filename: $!";while (<FILE>) {
# do something with $_
}
close FILE;
Vorm posted this at 01:21 — 1st November 2000.
They have: 62 posts
Joined: May 2000
Well, actually, I'm pretty sure PERL is an acronym, and acronyms are capitalized, so...
Yeah, the split thing was different. Ditto for the no () around the push.
Rob Pengelly posted this at 01:29 — 1st November 2000.
They have: 850 posts
Joined: Jul 1999
Vorm, I believe that Larry Wall, Perl's creator requested that it be written as Perl, rather than PERL.
japhy posted this at 02:50 — 1st November 2000.
They have: 161 posts
Joined: Dec 1999
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