[33037] in Perl-Users-Digest
Perl-Users Digest, Issue: 4313 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Sat Nov 22 03:09:16 2014
Date: Sat, 22 Nov 2014 00:09:03 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Sat, 22 Nov 2014 Volume: 11 Number: 4313
Today's topics:
A hash of references to arrays of references to hashes. <see.my.sig@for.my.address>
Re: A hash of references to arrays of references to has <gamo@telecable.es>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 21 Nov 2014 21:20:48 -0800
From: Robbie Hatley <see.my.sig@for.my.address>
Subject: A hash of references to arrays of references to hashes... is there a better way?
Message-Id: <gfednc6pXr-tgO3JnZ2dnUVZ5703t52d@giganews.com>
Greetings, group. I've been away several years, but I'm back. :-)
I've changed jobs (several times), changed homes (several times).
I've also changed programming platforms. I got rid of Windows 2000
and djgpp, and I'm currently using the following 2 platforms:
1. Perl on Cygwin on Win 8.1 on notebook computer
2. Perl on Point Linux on desktop computer
I'd gotten somewhat good at Perl, 2005-2008, stopped using it
for a while (got distracted), but started getting back into it
November 2014. I'm taking up a program I started writing in 2005
but never finished. (At least not in Perl; I have a version
written in C++, but that only works on djgpp on Win2K; not portable.)
This program I'm writing will eventually be a duplicate file finding
and erasing program. I've pasted what I've written so far at the end
of this message for reference.
This program uses a hash of references to arrays of references
to hashes. (Gulp.) Seems to me there's got to be an easier way.
In C++ I just use "multimaps" from the C++ Standard Template
Library. Maybe there's something like that in CPAN but I haven't
looked yet.
My question is this: do the programmers here see any places in what
I've written below where things could be expressed more briefly or
clearly?
The part where I'm adding file-record hashes to arrays seems clunky
to me. The idea is this: We're riffling through all files in the
current directory, storing file records as hashes in arrays of
same-file-size, with the arrays being inserted into a hash keyed
by file size. So, if a file of same size as the current file has
been processed already, then add record for current file to the
appropriate array; otherwise, create a new array and insert it
into the outer hash. But the way I have this implemented below
is kinda ugly. Is there a better way of doing this?
And the following line looks too complicated to me; it works,
but is there a better way to do this?
foreach my $HashRef (@{$CurDirFiles{$Size}})
Here's the entire program (what I've written of it so far) for
reference:
#!/usr/bin/perl
################################################################################
# dedup3 #
# Duplicate file finding/erasing program. #
# Written by Robbie Hatley, starting 2005-06-21, as a "learn Perl" exercise. #
# Plan: Recursively descend directory tree starting from current working #
# directory, and make a master list of all files encountered on this branch. #
# Order the list by size. Within each size group, compare each file, from #
# left to right, to all the files to its right. If a duplicate pair is found, #
# alert user and get user input. Give user these choices: #
# 1. Erase left file #
# 2. Erase right file #
# 3. Ignore this pair of duplicate files and move to next #
# 4. Quit #
# If user elects to delete a file, delete it, then move to next duplicate. #
# Edit history: #
# Tue Jun 21, 2005 - Started writing it. #
# Thu Nov 20, 2014 - Getting back to this exercise after 9-year hiatus. #
################################################################################
use v5.14;
use strict;
use warnings;
use Cwd;
sub time_from_mtime;
sub date_from_mtime;
my $CurDir;
my %CurDirFiles;
$CurDir = getcwd();
print "CWD = ", $CurDir, "\n";
opendir(my $Dot, ".") or die "Can\'t open directory. $!";
while (my $FileName=readdir($Dot))
{
my ($dev, $ino, $mode, $nlink, $uid,
$gid, $rdev, $size, $atime, $mtime,
$ctime, $blksize, $blocks)
= stat($FileName);
my $ModDate = date_from_mtime($mtime);
my $ModTime = time_from_mtime($mtime);
my $Size = -s _ ;
my $Type;
if ( -d _ )
{
$Type = "Dir";
}
else
{
$Type = "File";
}
if ($CurDirFiles{$Size})
{
$CurDirFiles{$Size} =
[
@{$CurDirFiles{$Size}},
{
"Date" => $ModDate,
"Time" => $ModTime,
"Type" => $Type,
"Size" => $Size,
"Attr" => $mode,
"Name" => $FileName
}
];
}
else
{
$CurDirFiles{$Size} =
[
{
"Date" => $ModDate,
"Time" => $ModTime,
"Type" => $Type,
"Size" => $Size,
"Attr" => $mode,
"Name" => $FileName
}
];
}
};
closedir($Dot);
foreach my $Size (reverse sort {$a<=>$b} keys %CurDirFiles)
{
##### Could this next line be written a better way? #####
foreach my $HashRef (@{$CurDirFiles{$Size}})
{
print($$HashRef{Date}, " ");
print($$HashRef{Time}, " ");
print($$HashRef{Type}, " ");
print($$HashRef{Size}, " ");
print($$HashRef{Attr}, " ");
print($$HashRef{Name}, "\n");
}
}
sub date_from_mtime
{
my $TimeDate = scalar localtime shift @_;
my $Date = substr ($TimeDate, 0, 10);
$Date .= ", ";
$Date .= substr ($TimeDate, 20, 4);
return $Date;
}
sub time_from_mtime
{
my $TimeDate = scalar localtime shift @_;
my $Time = substr ($TimeDate, 11, 8);
return $Time;
}
--
Robbie Hatley
lonewolf [at] well [dot] com
------------------------------
Date: Sat, 22 Nov 2014 08:06:04 +0100
From: gamo <gamo@telecable.es>
Subject: Re: A hash of references to arrays of references to hashes... is there a better way?
Message-Id: <m4pckr$3oh$1@speranza.aioe.org>
El 22/11/14 a las 06:20, Robbie Hatley escribió:
> and djgpp, and I'm currently using the following 2 platforms:
> 1. Perl on Cygwin on Win 8.1 on notebook computer
> 2. Perl on Point Linux on desktop computer
Since you use 2) you can't code the thing as if
`locate -b "$filename"` does not exists.
Other considerations are that after you find
candidates to dupes by file attributes, you must
really check if they are dupes, so use of
Digest::SHA3 is advisable.
--
http://www.telecable.es/personales/gamo/
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
Administrivia:
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------------------------------
End of Perl-Users Digest V11 Issue 4313
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