Re^2: using grep on a directory to list files for a single date

OK, sort of got somthing working but im sure there is a more "efficent" way to do it as its still returning a large array and loads of the elements are empty???

sub list{ 

my $path=shift;
my $comp=shift;
if (! -e $path){die "Error : $path $!\n";}
opendir(DIR,$path) or die "Error : $path $!\n";
return sort
 map {  my ($d,$m,$y) = (localtime( (stat "$path/$_")[9] ) )[3..5]; 
        $m+=1; $y+=1900;
        $m=($m<10)?"0$m":$m;
        $d=($d<10)?"0$d":$d;
        my $date = "$d/$m/$y";
        if($date eq $comp){"$_\n"};
    } grep(!/^(\.+?)$/,readdir(DIR));
}
[download]

any ideas??
Thanks for you help on this so far.
(goin to try the while() loop next)

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Re^3: using grep on a directory to list files for a single date by ikegami (Patriarch) on Dec 01, 2004 at 15:07 UTC
What is the `if` in the map trying to do? if `$date eq $comp` is false, `map` adds an undef to the returned list. if `$date eq $comp` is true, `map` returns "$_\n". Below, I assume that you're were trying to filter out dates that don't match. Filtering is `grep`'s job, not `map`'s. The "empty" elements you're getting are the undef returned by `map` when `$date eq $comp` is false. `$!` doesn't have any meaningful value after calling `-e`. The `-e` is redundant. `opendir` will fail if the dir doesn't exist, and you already handle that. The capture in `/^(\.+?)$/` wastes time. The `?` is meaningless. I wonder if `$_ eq '.' \|\| $_ eq '..'` would be faster. It's probably faster to divide $comp in $year, $month, $day than to convert all the mtimes to strings. sub list { my ($path, $comp) = @_; $comp =~ m#^(..)/(..)/(....)$# or die("Error: Badly formatted \$comp.\n"); my $comp_d = $1; my $comp_m = $2; my $comp_y = $3; local *DIR; opendir(DIR, $path) or die("Error: Unable to open directory $path: $!\n"); my @filtered_listing; while (<DIR>) { next if /^\.+$/; my ($mtime_d, $mtime_m, $mtime_y) = (localtime( (stat "$path/$_")[9] ) )[3..5]; next unless ( $mtime_d == $comp_d && $mtime_m == $comp_m && $mtime_y == $comp_y ); push(@filtered_listing, $_); } return sort @filtered_listing; } [download]	[reply] [d/l] [select]
Re^4: using grep on a directory to list files for a single date by ikegami (Patriarch) on Dec 01, 2004 at 16:25 UTC
oh, you might want to return a reference to the array instead of the array itself, especially if it's big. `... return [ sort @filtered_listing ]; } my $array = list(...); foreach (0..$#$array) { ... $$array[$_] ... }` [download]	[reply] [d/l]
Re^3: using grep on a directory to list files for a single date by revdiablo (Prior) on Dec 01, 2004 at 18:25 UTC
ikegami has already posted an excellent reply, showing exactly how to do it with while. That is probably the best way to solve this particular problem, but I thought I would show you how to use map to filter out elements, for your future reference: `my @array = qw(foo bar baz qux); my @newarray = map { my $foo = $_; $foo =~ s/./\u$&/; # useless example $foo =~ /Ba/ ? $foo : () } grep { /a/ } @array;` [download] The key here is to return an empty list when the condition fails. It's neat that we can do this with map, but it's usually better to use another grep: `my @array = qw(foo bar baz qux); my @newarray = grep { /Ba/ } map { my $foo = $_; $foo =~ s/./\u$&/; # useless example $foo } grep { /a/ } @array;` [download] HTH	[reply] [d/l] [select]