Efficiency Question

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

Hello fellow monks. I am not sure if I chose the best title, but its all I could think of. I am wondering if there is a better way to accomplish the task I am working on.

I am working on a script that reads the names of several directories into a hash and then 1) prints the keys to that hash into a benchmark file and 2) prints a report of all the dirs it found. I was later asked to add the ability to read some dir names from a config file and that those names should be skipped in the printed report, but should still be printed into the benchmark file. Here is the solution I came up with. I have stripped the code down to what should be the relevant parts.

use strict;

my ($config_dirs) = &read_conf();
my ($dirs) = &search_dirs();
&print();

sub read_conf {
       my %config_dirs;
       .... # read the conf file
       return \%config_dirs;
}

sub search_dirs {
       my %dirs;
       .... # search the dirs
       return \%dirs;
}

sub print {
       foreach (keys %$dirs) {
              my $no_print = 0;
              foreach my $skip (keys %$config_dirs) {
                     if (/^$skip/) {
                            $no_print = 1;
                            last;
                     }
              }
       print REPORT "$_\n" unless ($no_print == 1);
       }
}
[download]

Now that works, but it just seems like there has to be a better way to do that. Any suggestions?

If it helps some examples of what would be in the config file would be things like /home and some of the found dirs would be things like /home/bob and /home/ted. Thanks.

-Prime

Comment on Efficiency Question Download Code

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Re: Efficiency Question
by dragonchild (Archbishop) on Mar 21, 2002 at 19:33 UTC

foreach (keys %$dirs)
{
    next if $config_dirs->{$skip};
    # Do stuff
}
---- Or ----
foreach (keys %$dirs)
{
    next if grep {/^$skip/} keys %$config_dirs;
    # Do stuff
}
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Re: Re: Efficiency Question

by PrimeLord (Pilgrim) on Mar 21, 2002 at 19:37 UTC

I'm sorry I forgot to address that. The dirs in %dirs will never exactly match the dirs listed in %config_dirs. The config file will only contain high level directories like /home /etc /usr etc. But the %dirs is going to contain things like /usr/local/bin etc. so an exact match won;t be possible.

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Re^3: Efficiency Question

by tadman (Prior) on Mar 21, 2002 at 20:33 UTC

my $skip = join ('|', map {quotemeta} keys %$config_dirs);

dragonchild

foreach (keys %$dirs)
{
    next if /^($skip)/;
    # Do stuff
}
[download]

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Re: Re: Re: Efficiency Question

by CukiMnstr (Deacon) on Mar 21, 2002 at 21:00 UTC

sub print_report {
    foreach (keys %$dirs) {
        print BENCHMARK $_;
        m#^/[^/]+/#;
        next if defined $config_dirs->{$&};
        print "$_\n";
    }
}
[download]

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Re: Efficiency Question
by vladb (Vicar) on Mar 21, 2002 at 20:16 UTC

print

"There is no system but GNU, and Linux is one of its kernels." -- Confession of Faith

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