Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

hi ive wrote a script then looks in directories, reads a file in each directory, and grabs some values in the file. This seems to work. But when i print the output, i get weird results. 
#!/usr/bin/perl

#configuration thingies
$lsdir = '/var/www/foto'; #this is the dir to look in
$dir = '2004';            #hard to explain this one, but it doesnt mat
+ter much
$year = '04';             #what is the value of yy in yy-mm-dd in on o
+f the values grabbed

##############################################
foreach (`ls $lsdir`) { #do a ls
        if (/album(\d{2,})/) { 
                $album_nr = $1;
                $file = "$lsdir" . '/album' . "$album_nr" . '/album.da
+t';
                open FILE, "$file" or
                        warn "coud not open $file: $! \n" and next; #s
+o this looks in each /var/www/foto/album{2,}/album.dat
                $/ = ';'; #each string in album.dat is seperated by a 
+;
                <FILE>;<FILE>;
                $_ = <FILE>;
                s/\n//g;
                $name = (/.*\"(.*)\"/)[0]; #get the name from album.da
+t
                <FILE>;
                $_ = <FILE>;
                s/\n//g;
                ($desc = (/.*\"(.+)\"/)[0]) || ($desc = "");# get the 
+description from album.dat
                while (<FILE>) {
                        if (/parentAlbumName/) {
                                $_ = <FILE>;
                                $file_dir = (/.*\"(.+)\"/)[0]; 
                                last;
                        }
                } #get the virtual directory from album.dat
#all the values needed are stored. now some conditions the values shou
+ld meet, or else get lost.
                if ($file_dir eq $dir) {
                        if ($name =~ /\d\d\-\d\d\-\d\d/) {
                                $date = "$&";
                                $date =~ s/\-//g;
                                unless ($date =~ /^$year/) {
                                        warn "the date of album $album
+_nr ($name) doesn't seem to be in yy-mm-dd format. skipping..\n";
                                        next;
                                }
                        } else {
                                warn "the title of album $album_nr ($n
+ame) doesn't seem to contain a date, or a date in yy-mm-dd format. sk
+ipping..\n";
                                next;
                        }
#so if the values met those conditions, store them in @names.
                        unshift @names, "$album_nr:$name:$desc\n";
                }
        }
}

print "@names"; #print

[download]
------------end of program
ok, now the real problem: when i run it in bash i get this output: 
the title of album 107 (Eerste kwartaal van 2004) doesn't seem to cont
+ain a date, or a date in yy-mm-dd format. skipping..
the title of album 131 (Untitled) doesn't seem to contain a date, or a
+ date in yy-mm-dd format. skipping..
:by SuuZ, Oxi, Vaisha, SPoT_D, SCVNGR, Groenshirt & TeKnoID
 130:04-05-05 Zwolle:by Oxi & SPoT_D
 124:04-04-28 Amsterdam:by Oxi
 118:04-04-17 Hilversum:by Apraxia
 117:04-04-17 Zeist:by SuuZ
 116:04-04-17 Rotterdam:by SuuZ
 113:04-04-17 Hilversum:by Oxi
 112:04-04-17 Zeist:by Vaisha & Oxi
 111:04-04-17 Bazart Anti Lounge:by Vaisha
 110:04-04-10 Maarssen:by SPoT_D & Oxi
 106:04-04-03 Tilburg:>Groene Shirt</a>
 105:04-04-02 Hypnoskull Nighttown:by Apraxia
 104:04-04-03 Tilburg:by Vaisha
 103:04-04-17 Bazart Anti-Lounge:by Apraxia

[download]
the first two sentences are ok.. but after that comes this: 
:by SuuZ, Oxi, Vaisha, SPoT_D, SCVNGR, Groenshirt & TeKnoID

[download]
and that should've been: 
75:04-04-29 Teknival Noord-Frankrijk:by SuuZ, Oxi, Vaisha, SPoT_D, SCV
+NGR, Groenshirt & TeKnoID

[download]
as you can see, this really sucks. one variable seems to replace another in (only) the first value of the array @names.
i have completely no idea why this happens, so i thought mayb you would :)

if you could help me with this, thanxs a lot

Replies are listed 'Best First'.
Re: Problem parsing and printing data from file
by Roy Johnson (Monsignor) on May 06, 2004 at 14:47 UTC
    I haven't figured out the main problem, yet, but I'll offer some suggestions for tidying this up: 
    #     $file = "$lsdir" . '/album' . "$album_nr" . '/album.dat';
# becomes
$file = "$lsdir/album$album_nr/album.dat";

#      open FILE, "$file" or
# Don't quote variables unless you're constructing new strings
open FILE $file or

#  $name = (/.*\"(.*)\"/)[0];
# no need for leading .*; better as
($name) = /"(.*)"/;

#  s/\n//g;
#  ($desc = (/.*\"(.+)\"/)[0]) || ($desc = "");
# Better as
tr/\n//d;
($desc) = /"(.+)"/;

    [download]
    Okay, I just thought of a possibility: There is a carriage return in the $name field for that album. In that case, the data is all there, but when you print it, the carriage return is causing the data that follows it to overwrite everything before it.
    The PerlMonk tr/// Advocate
[reply]
[d/l]
      hey, that is the solution :)

      thanks a lot..
      (and for the code style tips) :)

      i had ours of headache on this one, but to go deeper in on this problem(so i don't make this error in the future):
      what exactly is the difference between a \n and \r?
      never really understood that

      tnx
[reply]
        oh.. and why is tr/\n//d better that s/\n//g ?

        :)
[reply]

Back to Seekers of Perl Wisdom