Re^2: Compare 2 arrays

I liked your code. A few suggestions, but also not tested!

Use "/" instead of "\\" for windows file paths
I think some extra filtering is necessary on the $namesIn file?
for opendir, add a die message if fails
for readdir, skip all but simple files - maybe here makes no difference, but I would do it.

Perhaps something like this???

#!usr/bin/perl
use strict;
use warnings;

my $files = "C:/Directory";
my $list  = "C:/Test.sdf";

my %keepList;

open my $namesIn, '<', $list or die "Failed to open file: $!\n";

# minor updates to this loop #####################

while (my $line = <$namesIn>) #updated #######
{
   my $sdf_file;
   #next unless ($sdf_file) = $line =~ /(\w+\.nfo)"$/;
   #this regex should work equally well
   next unless ($sdf_file) = $line =~ /(\w+\.nfo)/;
   $keepList{$sdf_file} = 1;
   print "keeping $sdf_file\n"; #update for debugging #######
}
close $namesIn;

opendir my ($filesScan), $files or die "unable to open dir $!";

while (my $filename = readdir $filesScan) 
{
    next unless -f "$files/$filename";  #only simple files allowed
                                        #skip . and .. or other dirs
    next if exists $keepList{$filename};
    
    unlink "$files/$filename" or warn qq{cannot delete $filename: $!+}
+;
}

closedir $filesScan;
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Re^3: Compare 2 arrays by niceguy (Initiate) on Jun 28, 2016 at 15:58 UTC
Hi Marshall, Thank you for your responds and your suggestions. Unfortunately your codes also delete all the files in the directory. Please let me know if you have other ideas.	[reply]
Re^4: Compare 2 arrays by Marshall (Canon) on Jun 28, 2016 at 18:34 UTC
Looks like the keepList hash is not being populated correctly. I tweaked the code a bit in my post. See how you do with the modifications. I added a print statement. Make sure that it is printing correctly the files that should be kept! Update: Another point, when you run the code warnings matter! My previous code with `while (<$namesIn>)` would have produced a warning if not an outright failure because $line was not declared! The new code, `while (my $line = <$namesIn>)` "should work". This kind of error is common in untested code. I would have expected that you find that and fix it on your own. When debugging code, "print" is your best friend. Add more print statements to see what the code is actually doing. I put in one for the keepList hash because I suspect that is where the problem lies. Add another one before the unlink to see what is going on there. The Perl debugger is also helpful, but print works so well that I seldom need to resort to that even when I am writing C code. First, debug the code that reads the SDF file and gets the .nfo file names. Then debug the code that does the unlink (i.e. delete in Windows lingo).	[reply] [d/l] [select]