[31560] in Perl-Users-Digest
Perl-Users Digest, Issue: 2819 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Feb 16 06:09:23 2010
Date: Tue, 16 Feb 2010 03:09:10 -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 Tue, 16 Feb 2010 Volume: 11 Number: 2819
Today's topics:
Extracting PDF document metadata in Perl? <anon40629@hotmail.com>
Re: Extracting PDF document metadata in Perl? <tadmc@seesig.invalid>
Re: How to get offset position from unpack()? <ben@morrow.me.uk>
Posting Guidelines for comp.lang.perl.misc ($Revision: tadmc@seesig.invalid
readdir: is there a way to reset cursor to beginning? <patrickh@gmail.com>
Re: readdir: is there a way to reset cursor to beginnin <jurgenex@hotmail.com>
Re: readdir: is there a way to reset cursor to beginnin <patrickh@gmail.com>
Re: readdir: is there a way to reset cursor to beginnin <patrickh@gmail.com>
Re: readdir: is there a way to reset cursor to beginnin <someone@example.com>
Re: readdir: is there a way to reset cursor to beginnin <uri@StemSystems.com>
Re: readdir: is there a way to reset cursor to beginnin <bugbear@trim_papermule.co.uk_trim>
use strict... <robin1@cnsp.com>
Re: use strict... (Randal L. Schwartz)
Re: use strict... <xemoth@gmail.com>
Re: use strict... <RedGrittyBrick@spamweary.invalid>
Re: use strict... <patrickh@gmail.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Mon, 15 Feb 2010 16:17:47 -0800
From: "Mark G." <anon40629@hotmail.com>
Subject: Extracting PDF document metadata in Perl?
Message-Id: <zo6dnef9E7y7eeTWnZ2dnUVZ_rednZ2d@posted.palinacquisition>
Good afternoon.
I am using CAM::PDF to extract information from a large library of
PDF files. I cannot determine how to extract standard metadata
(author, title, etc.) Is it possible to do this with CAM::PDF? If not,
can anyone suggest another Perl package that I can use to do this?
Thank you
-Mark
------------------------------
Date: Mon, 15 Feb 2010 19:41:06 -0600
From: Tad McClellan <tadmc@seesig.invalid>
Subject: Re: Extracting PDF document metadata in Perl?
Message-Id: <slrnhnjtmn.pp0.tadmc@tadbox.sbcglobal.net>
Mark G. <anon40629@hotmail.com> wrote:
> Good afternoon.
Please do not multipost, crosspost instead.
http://oakroadsystems.com/genl/unice.htm#xpost
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
------------------------------
Date: Mon, 15 Feb 2010 20:48:19 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: How to get offset position from unpack()?
Message-Id: <jhoo47-srn.ln1@osiris.mauzo.dyndns.org>
Quoth "jl_post@hotmail.com" <jl_post@hotmail.com>:
> Hi,
>
> The unpack() function is very, very useful for me, as I regularly
> do a lot of unpacking of non-Perl-created data strings to see what
> information they hold. If I didn't have the use of the unpack()
> function, certain tasks would be much more difficult.
>
> However, there's something I want to do with unpack() that I
> haven't figured out how to do: I'd like to unpack part of a string,
> but keep track of where the unpacking ended, so I can resume unpacking
> the string (at a later time) where I left off.
~% perl -E'my $x = "aaa"; say for unpack "a2.", $x'
aa
2
~%
Ben
------------------------------
Date: Tue, 16 Feb 2010 02:13:41 -0600
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <OqudnYlyh8sozufWnZ2dnUVZ_ridnZ2d@giganews.com>
Outline
Before posting to comp.lang.perl.misc
Must
- Check the Perl Frequently Asked Questions (FAQ)
- Check the other standard Perl docs (*.pod)
Really Really Should
- Lurk for a while before posting
- Search a Usenet archive
If You Like
- Check Other Resources
Posting to comp.lang.perl.misc
Is there a better place to ask your question?
- Question should be about Perl, not about the application area
How to participate (post) in the clpmisc community
- Carefully choose the contents of your Subject header
- Use an effective followup style
- Speak Perl rather than English, when possible
- Ask perl to help you
- Do not re-type Perl code
- Provide enough information
- Do not provide too much information
- Do not post binaries, HTML, or MIME
Social faux pas to avoid
- Asking a Frequently Asked Question
- Asking a question easily answered by a cursory doc search
- Asking for emailed answers
- Beware of saying "doesn't work"
- Sending a "stealth" Cc copy
Be extra cautious when you get upset
- Count to ten before composing a followup when you are upset
- Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------
Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
This newsgroup, commonly called clpmisc, is a technical newsgroup
intended to be used for discussion of Perl related issues (except job
postings), whether it be comments or questions.
As you would expect, clpmisc discussions are usually very technical in
nature and there are conventions for conduct in technical newsgroups
going somewhat beyond those in non-technical newsgroups.
The article at:
http://www.catb.org/~esr/faqs/smart-questions.html
describes how to get answers from technical people in general.
This article describes things that you should, and should not, do to
increase your chances of getting an answer to your Perl question. It is
available in POD, HTML and plain text formats at:
http://www.rehabitation.com/clpmisc.shtml
For more information about netiquette in general, see the "Netiquette
Guidelines" at:
http://andrew2.andrew.cmu.edu/rfc/rfc1855.html
A note to newsgroup "regulars":
Do not use these guidelines as a "license to flame" or other
meanness. It is possible that a poster is unaware of things
discussed here. Give them the benefit of the doubt, and just
help them learn how to post, rather than assume that they do
know and are being the "bad kind" of Lazy.
A note about technical terms used here:
In this document, we use words like "must" and "should" as
they're used in technical conversation (such as you will
encounter in this newsgroup). When we say that you *must* do
something, we mean that if you don't do that something, then
it's unlikely that you will benefit much from this group.
We're not bossing you around; we're making the point without
lots of words.
Do *NOT* send email to the maintainer of these guidelines. It will be
discarded unread. The guidelines belong to the newsgroup so all
discussion should appear in the newsgroup. I am just the secretary that
writes down the consensus of the group.
Before posting to comp.lang.perl.misc
Must
This section describes things that you *must* do before posting to
clpmisc, in order to maximize your chances of getting meaningful replies
to your inquiry and to avoid getting flamed for being lazy and trying to
have others do your work.
The perl distribution includes documentation that is copied to your hard
drive when you install perl. Also installed is a program for looking
things up in that (and other) documentation named 'perldoc'.
You should either find out where the docs got installed on your system,
or use perldoc to find them for you. Type "perldoc perldoc" to learn how
to use perldoc itself. Type "perldoc perl" to start reading Perl's
standard documentation.
Check the Perl Frequently Asked Questions (FAQ)
Checking the FAQ before posting is required in Big 8 newsgroups in
general, there is nothing clpmisc-specific about this requirement.
You are expected to do this in nearly all newsgroups.
You can use the "-q" switch with perldoc to do a word search of the
questions in the Perl FAQs.
Check the other standard Perl docs (*.pod)
The perl distribution comes with much more documentation than is
available for most other newsgroups, so in clpmisc you should also
see if you can find an answer in the other (non-FAQ) standard docs
before posting.
It is *not* required, or even expected, that you actually *read* all of
Perl's standard docs, only that you spend a few minutes searching them
before posting.
Try doing a word-search in the standard docs for some words/phrases
taken from your problem statement or from your very carefully worded
"Subject:" header.
Really Really Should
This section describes things that you *really should* do before posting
to clpmisc.
Lurk for a while before posting
This is very important and expected in all newsgroups. Lurking means
to monitor a newsgroup for a period to become familiar with local
customs. Each newsgroup has specific customs and rituals. Knowing
these before you participate will help avoid embarrassing social
situations. Consider yourself to be a foreigner at first!
Search a Usenet archive
There are tens of thousands of Perl programmers. It is very likely
that your question has already been asked (and answered). See if you
can find where it has already been answered.
One such searchable archive is:
http://groups.google.com/advanced_search
If You Like
This section describes things that you *can* do before posting to
clpmisc.
Check Other Resources
You may want to check in books or on web sites to see if you can
find the answer to your question.
But you need to consider the source of such information: there are a
lot of very poor Perl books and web sites, and several good ones
too, of course.
Posting to comp.lang.perl.misc
There can be 200 messages in clpmisc in a single day. Nobody is going to
read every article. They must decide somehow which articles they are
going to read, and which they will skip.
Your post is in competition with 199 other posts. You need to "win"
before a person who can help you will even read your question.
These sections describe how you can help keep your article from being
one of the "skipped" ones.
Is there a better place to ask your question?
Question should be about Perl, not about the application area
It can be difficult to separate out where your problem really is,
but you should make a conscious effort to post to the most
applicable newsgroup. That is, after all, where you are the most
likely to find the people who know how to answer your question.
Being able to "partition" a problem is an essential skill for
effectively troubleshooting programming problems. If you don't get
that right, you end up looking for answers in the wrong places.
It should be understood that you may not know that the root of your
problem is not Perl-related (the two most frequent ones are CGI and
Operating System related), so off-topic postings will happen from
time to time. Be gracious when someone helps you find a better place
to ask your question by pointing you to a more applicable newsgroup.
How to participate (post) in the clpmisc community
Carefully choose the contents of your Subject header
You have 40 precious characters of Subject to win out and be one of
the posts that gets read. Don't waste them. Take care while
composing them, they are the key that opens the door to getting an
answer.
Spend them indicating what aspect of Perl others will find if they
should decide to read your article.
Do not spend them indicating "experience level" (guru, newbie...).
Do not spend them pleading (please read, urgent, help!...).
Do not spend them on non-Subjects (Perl question, one-word
Subject...)
For more information on choosing a Subject see "Choosing Good
Subject Lines":
http://www.cpan.org/authors/id/D/DM/DMR/subjects.post
Part of the beauty of newsgroup dynamics, is that you can contribute
to the community with your very first post! If your choice of
Subject leads a fellow Perler to find the thread you are starting,
then even asking a question helps us all.
Use an effective followup style
When composing a followup, quote only enough text to establish the
context for the comments that you will add. Always indicate who
wrote the quoted material. Never quote an entire article. Never
quote a .signature (unless that is what you are commenting on).
Intersperse your comments *following* each section of quoted text to
which they relate. Unappreciated followup styles are referred to as
"top-posting", "Jeopardy" (because the answer comes before the
question), or "TOFU" (Text Over, Fullquote Under).
Reversing the chronology of the dialog makes it much harder to
understand (some folks won't even read it if written in that style).
For more information on quoting style, see:
http://web.presby.edu/~nnqadmin/nnq/nquote.html
Speak Perl rather than English, when possible
Perl is much more precise than natural language. Saying it in Perl
instead will avoid misunderstanding your question or problem.
Do not say: I have variable with "foo\tbar" in it.
Instead say: I have $var = "foo\tbar", or I have $var = 'foo\tbar',
or I have $var = <DATA> (and show the data line).
Ask perl to help you
You can ask perl itself to help you find common programming mistakes
by doing two things: enable warnings (perldoc warnings) and enable
"strict"ures (perldoc strict).
You should not bother the hundreds/thousands of readers of the
newsgroup without first seeing if a machine can help you find your
problem. It is demeaning to be asked to do the work of a machine. It
will annoy the readers of your article.
You can look up any of the messages that perl might issue to find
out what the message means and how to resolve the potential mistake
(perldoc perldiag). If you would like perl to look them up for you,
you can put "use diagnostics;" near the top of your program.
Do not re-type Perl code
Use copy/paste or your editor's "import" function rather than
attempting to type in your code. If you make a typo you will get
followups about your typos instead of about the question you are
trying to get answered.
Provide enough information
If you do the things in this item, you will have an Extremely Good
chance of getting people to try and help you with your problem!
These features are a really big bonus toward your question winning
out over all of the other posts that you are competing with.
First make a short (less than 20-30 lines) and *complete* program
that illustrates the problem you are having. People should be able
to run your program by copy/pasting the code from your article. (You
will find that doing this step very often reveals your problem
directly. Leading to an answer much more quickly and reliably than
posting to Usenet.)
Describe *precisely* the input to your program. Also provide example
input data for your program. If you need to show file input, use the
__DATA__ token (perldata.pod) to provide the file contents inside of
your Perl program.
Show the output (including the verbatim text of any messages) of
your program.
Describe how you want the output to be different from what you are
getting.
If you have no idea at all of how to code up your situation, be sure
to at least describe the 2 things that you *do* know: input and
desired output.
Do not provide too much information
Do not just post your entire program for debugging. Most especially
do not post someone *else's* entire program.
Do not post binaries, HTML, or MIME
clpmisc is a text only newsgroup. If you have images or binaries
that explain your question, put them in a publically accessible
place (like a Web server) and provide a pointer to that location. If
you include code, cut and paste it directly in the message body.
Don't attach anything to the message. Don't post vcards or HTML.
Many people (and even some Usenet servers) will automatically filter
out such messages. Many people will not be able to easily read your
post. Plain text is something everyone can read.
Social faux pas to avoid
The first two below are symptoms of lots of FAQ asking here in clpmisc.
It happens so often that folks will assume that it is happening yet
again. If you have looked but not found, or found but didn't understand
the docs, say so in your article.
Asking a Frequently Asked Question
It should be understood that you may have missed the applicable FAQ
when you checked, which is not a big deal. But if the Frequently
Asked Question is worded similar to your question, folks will assume
that you did not look at all. Don't become indignant at pointers to
the FAQ, particularly if it solves your problem.
Asking a question easily answered by a cursory doc search
If folks think you have not even tried the obvious step of reading
the docs applicable to your problem, they are likely to become
annoyed.
If you are flamed for not checking when you *did* check, then just
shrug it off (and take the answer that you got).
Asking for emailed answers
Emailed answers benefit one person. Posted answers benefit the
entire community. If folks can take the time to answer your
question, then you can take the time to go get the answer in the
same place where you asked the question.
It is OK to ask for a *copy* of the answer to be emailed, but many
will ignore such requests anyway. If you munge your address, you
should never expect (or ask) to get email in response to a Usenet
post.
Ask the question here, get the answer here (maybe).
Beware of saying "doesn't work"
This is a "red flag" phrase. If you find yourself writing that,
pause and see if you can't describe what is not working without
saying "doesn't work". That is, describe how it is not what you
want.
Sending a "stealth" Cc copy
A "stealth Cc" is when you both email and post a reply without
indicating *in the body* that you are doing so.
Be extra cautious when you get upset
Count to ten before composing a followup when you are upset
This is recommended in all Usenet newsgroups. Here in clpmisc, most
flaming sub-threads are not about any feature of Perl at all! They
are most often for what was seen as a breach of netiquette. If you
have lurked for a bit, then you will know what is expected and won't
make such posts in the first place.
But if you get upset, wait a while before writing your followup. I
recommend waiting at least 30 minutes.
Count to ten after composing and before posting when you are upset
After you have written your followup, wait *another* 30 minutes
before committing yourself by posting it. You cannot take it back
once it has been said.
AUTHOR
Tad McClellan and many others on the comp.lang.perl.misc newsgroup.
--
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"
------------------------------
Date: Mon, 15 Feb 2010 21:26:04 -0800 (PST)
From: "Patrick H." <patrickh@gmail.com>
Subject: readdir: is there a way to reset cursor to beginning?
Message-Id: <0298ad8c-a26c-4e9f-8d40-60dc95f4a624@h2g2000yqj.googlegroups.com>
Hi, I am toying around with the directory operations chapter of
"Learning Perl" and ran into a bit of a snag.
I am trying to open a directory, output all the -f files to a @files
array and all the -d files to a @folders array. The problem is it
seems to only work for the first instance of readdir I use; they both
work individually when I comment the other out, but when I have them
both only the first array is populated. Do I need to closedir and then
opendir again, or is there a way for me to reset the cursor (if that
is even the right terminology)?
Below is my code, and advice would be appreciated.
Patrick H.
#!/usr/bin/perl -w
use strict;
# folder to scan
my $folder = 'c:/';
# open folder
opendir C_DRIVE, $folder or die "problem reading $folder: $!";
my @files = grep { -f "$folder/$_" } readdir(C_DRIVE); # all
files
my @folders = grep { -d "$folder/$_" } readdir(C_DRIVE); # all
folders
# close folder
closedir C_DRIVE;
# test results
print "your files: @files\n";
print "your folders: @folders\n";
------------------------------
Date: Mon, 15 Feb 2010 21:42:40 -0800
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: readdir: is there a way to reset cursor to beginning?
Message-Id: <tjbkn5l8kh31l7av16l6ptg8se7bu7dkrs@4ax.com>
"Patrick H." <patrickh@gmail.com> wrote:
>I am trying to open a directory, output all the -f files to a @files
>array and all the -d files to a @folders array. The problem is it
>seems to only work for the first instance of readdir I use; they both
>work individually when I comment the other out, but when I have them
>both only the first array is populated. Do I need to closedir and then
>opendir again, or is there a way for me to reset the cursor (if that
>is even the right terminology)?
You could try seek(). Although it is documented only for filehandles,
not directory handles. it just might work on directory handles, too.
>Below is my code, and advice would be appreciated.
>
[...]
># open folder
>opendir C_DRIVE, $folder or die "problem reading $folder: $!";
>
>my @files = grep { -f "$folder/$_" } readdir(C_DRIVE); # all
>files
>my @folders = grep { -d "$folder/$_" } readdir(C_DRIVE); # all
>folders
However a better approach would be to loop through all the files in a
single pass and assign them to @files or @folders as you read each
directory entry.
<sketch only, not actual code>
while (my $direntry = readdir (C_DRIVE))
if (-f $direntry) {push @files, $direntry};
if (-d $direntry) {push @folders, $direntry}
}
Or read then all into a one array, duplicate that array, and then filter
@folders = @files = readdir(...);
@folders = grep (-d ...., @folders);
@files = grep (-f ...., @files);
jue
>
># close folder
>closedir C_DRIVE;
>
># test results
>print "your files: @files\n";
>print "your folders: @folders\n";
>
------------------------------
Date: Mon, 15 Feb 2010 21:43:55 -0800 (PST)
From: "Patrick H." <patrickh@gmail.com>
Subject: Re: readdir: is there a way to reset cursor to beginning?
Message-Id: <91e5f52b-83f1-4ad6-a3a4-0cc941c97943@a5g2000yqi.googlegroups.com>
On Feb 15, 11:26=A0pm, "Patrick H." <patri...@gmail.com> wrote:
> Hi, I am toying around with the directory operations chapter of
> "Learning Perl" and ran into a bit of a snag.
>
> I am trying to open a directory, output all the -f files to a @files
> array and all the -d files to a @folders array. The problem is it
> seems to only work for the first instance of readdir I use; they both
> work individually when I comment the other out, but when I have them
> both only the first array is populated. Do I need to closedir and then
> opendir again, or is there a way for me to reset the cursor (if that
> is even the right terminology)?
>
> Below is my code, and advice would be appreciated.
>
> Patrick H.
>
> #!/usr/bin/perl -w
> use strict;
>
> # folder to scan
> my $folder =3D 'c:/';
>
> # open folder
> opendir C_DRIVE, $folder or die "problem reading $folder: $!";
>
> my @files =3D grep { -f "$folder/$_" } readdir(C_DRIVE); =A0 =A0 =A0# all
> files
> my @folders =3D grep { -d "$folder/$_" } readdir(C_DRIVE); =A0 =A0# all
> folders
>
> # close folder
> closedir C_DRIVE;
>
> # test results
> print "your files: @files\n";
> print "your folders: @folders\n";
With the risk of looking like I'm talking to myself, I came up with a
different way of doing it through just one readdir - figured I would
post what my solution ended up being.
-Patrick
# scope variables
my (@files,@folders);
# read directory
while (my $name =3D readdir C_DRIVE) {
push @files, $name if -f "$folder/$name";
push @folders, $name if -d "$folder/$name";
}
------------------------------
Date: Mon, 15 Feb 2010 21:48:25 -0800 (PST)
From: "Patrick H." <patrickh@gmail.com>
Subject: Re: readdir: is there a way to reset cursor to beginning?
Message-Id: <dc23df48-8840-40f4-b142-315b6702ed2f@b2g2000yqi.googlegroups.com>
On Feb 15, 11:42=A0pm, J=FCrgen Exner <jurge...@hotmail.com> wrote:
> However a better approach would be to loop through all the files in a
> single pass and assign them to @files or @folders as you read each
> directory entry.
>
> <sketch only, not actual code>
>
> =A0 =A0 =A0 =A0 while (my $direntry =3D readdir (C_DRIVE))
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 if (-f $direntry) {push @files, $direntry=
};
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 if (-d $direntry) {push @folders, $dirent=
ry}
> =A0 =A0 =A0 =A0 }
Jue, thank you very much for the input. I came up with a similar
approach before I read your post. Always glad to have someone else's
opinion confirm what I was thinking :) .
Thanks,
Patrick
------------------------------
Date: Mon, 15 Feb 2010 23:35:09 -0800
From: "John W. Krahn" <someone@example.com>
Subject: Re: readdir: is there a way to reset cursor to beginning?
Message-Id: <OUren.96528$1m3.56209@newsfe11.iad>
Patrick H. wrote:
> Hi, I am toying around with the directory operations chapter of
> "Learning Perl" and ran into a bit of a snag.
>
> I am trying to open a directory, output all the -f files to a @files
> array and all the -d files to a @folders array. The problem is it
> seems to only work for the first instance of readdir I use; they both
> work individually when I comment the other out, but when I have them
> both only the first array is populated. Do I need to closedir and then
> opendir again, or is there a way for me to reset the cursor (if that
> is even the right terminology)?
perldoc -f rewinddir
> Below is my code, and advice would be appreciated.
>
> Patrick H.
>
>
> #!/usr/bin/perl -w
> use strict;
>
> # folder to scan
> my $folder = 'c:/';
>
> # open folder
> opendir C_DRIVE, $folder or die "problem reading $folder: $!";
>
> my @files = grep { -f "$folder/$_" } readdir(C_DRIVE); # all
> files
> my @folders = grep { -d "$folder/$_" } readdir(C_DRIVE); # all
> folders
my ( @files, @folders );
while ( my $file = readdir C_DRIVE ) {
push @files if -f "$folder/$file";
push @folders if -d "$folder/$file";
}
> # close folder
> closedir C_DRIVE;
>
> # test results
> print "your files: @files\n";
> print "your folders: @folders\n";
John
--
The programmer is fighting against the two most
destructive forces in the universe: entropy and
human stupidity. -- Damian Conway
------------------------------
Date: Tue, 16 Feb 2010 02:48:23 -0500
From: "Uri Guttman" <uri@StemSystems.com>
Subject: Re: readdir: is there a way to reset cursor to beginning?
Message-Id: <87iq9xk4e0.fsf@quad.sysarch.com>
>>>>> "JWK" == John W Krahn <someone@example.com> writes:
JWK> Patrick H. wrote:
>> Hi, I am toying around with the directory operations chapter of
>> "Learning Perl" and ran into a bit of a snag.
>>
>> I am trying to open a directory, output all the -f files to a @files
>> array and all the -d files to a @folders array. The problem is it
>> seems to only work for the first instance of readdir I use; they both
>> work individually when I comment the other out, but when I have them
>> both only the first array is populated. Do I need to closedir and then
>> opendir again, or is there a way for me to reset the cursor (if that
>> is even the right terminology)?
JWK> perldoc -f rewinddir
i recalled that was in there. but it isn't needed as you note below
JWK> my ( @files, @folders );
JWK> while ( my $file = readdir C_DRIVE ) {
JWK> push @files if -f "$folder/$file";
JWK> push @folders if -d "$folder/$file";
JWK> }
i hate all the duplicate pushes. try this on for size (untested :):
use File::Slurp ;
push( @{ -d "$folder/$_" ? \@folders : \@files }, $_ ) for read_dir( 'C:' );
that assumes if it ain't a dir, it is a file.
uri
--
Uri Guttman ------ uri@stemsystems.com -------- http://www.sysarch.com --
----- Perl Code Review , Architecture, Development, Training, Support ------
--------- Gourmet Hot Cocoa Mix ---- http://bestfriendscocoa.com ---------
------------------------------
Date: Tue, 16 Feb 2010 09:36:33 +0000
From: bugbear <bugbear@trim_papermule.co.uk_trim>
Subject: Re: readdir: is there a way to reset cursor to beginning?
Message-Id: <_a-dnV7iToW_-ufWnZ2dnUVZ8tti4p2d@brightview.co.uk>
Uri Guttman wrote:
>>>>>> "JWK" == John W Krahn <someone@example.com> writes:
>
> JWK> Patrick H. wrote:
> >> Hi, I am toying around with the directory operations chapter of
> >> "Learning Perl" and ran into a bit of a snag.
> >>
> >> I am trying to open a directory, output all the -f files to a @files
> >> array and all the -d files to a @folders array. The problem is it
> >> seems to only work for the first instance of readdir I use; they both
> >> work individually when I comment the other out, but when I have them
> >> both only the first array is populated. Do I need to closedir and then
> >> opendir again, or is there a way for me to reset the cursor (if that
> >> is even the right terminology)?
>
> JWK> perldoc -f rewinddir
>
> i recalled that was in there. but it isn't needed as you note below
>
> JWK> my ( @files, @folders );
> JWK> while ( my $file = readdir C_DRIVE ) {
> JWK> push @files if -f "$folder/$file";
> JWK> push @folders if -d "$folder/$file";
> JWK> }
>
> i hate all the duplicate pushes. try this on for size (untested :):
>
> use File::Slurp ;
> push( @{ -d "$folder/$_" ? \@folders : \@files }, $_ ) for read_dir( 'C:' );
Yikes. That's a triumph of ingenuity over clarity IMHO.
BugBear
------------------------------
Date: Mon, 15 Feb 2010 19:06:05 -0800 (PST)
From: Robin <robin1@cnsp.com>
Subject: use strict...
Message-Id: <4e6b74e3-fcc0-4d5e-9f61-4cac5e1bdcc1@f8g2000yqn.googlegroups.com>
I know this is a pretty stupid question, maybe, but is it better to
use strict? I have never gotten a concise answer to this question
because there reallty isn't any docs on it.
thanks,
-ro9bin
------------------------------
Date: Mon, 15 Feb 2010 19:33:44 -0800
From: merlyn@stonehenge.com (Randal L. Schwartz)
To: Robin <robin1@cnsp.com>
Subject: Re: use strict...
Message-Id: <86iq9xhn1j.fsf@blue.stonehenge.com>
>>>>> "Robin" == Robin <robin1@cnsp.com> writes:
Robin> I know this is a pretty stupid question, maybe, but is it better to
Robin> use strict? I have never gotten a concise answer to this question
Robin> because there reallty isn't any docs on it.
% perldoc strict
NAME
strict - Perl pragma to restrict unsafe constructs
SYNOPSIS
use strict;
use strict "vars";
use strict "refs";
use strict "subs";
use strict;
no strict "vars";
DESCRIPTION
[...]
You have a strange meaning of "isn't any". Care to elaborate?
print "Just another Perl hacker,"; # the original
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion
------------------------------
Date: Tue, 16 Feb 2010 00:45:06 -0800 (PST)
From: Owen <xemoth@gmail.com>
Subject: Re: use strict...
Message-Id: <73c073cf-be53-4de8-8f09-20e1dcabf811@b7g2000pro.googlegroups.com>
On Feb 16, 2:06=A0pm, Robin <rob...@cnsp.com> wrote:
> I know this is a pretty stupid question, maybe, but is it better to
> use strict? I have never gotten a concise answer to this question
> because there reallty isn't any docs on it.
> thanks,
> -ro9bin
There are a number of good reasons to use strict, however, in my case
I use it to help in de-bugging and all other side benefits are a
bonus.
90% of my errors are misspelt variables, IE, somwhere you have
# my $blah;
and later you use $blaj by mistake, it will tell you in its own
fashion that $blaj is perhaps a mistake.
Try this program to get get a message that would not be generated if
'use strict' was not used;
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
#!/usr/bin/perl
use strict;
my $blah;
$blaj =3D2;
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
You should also 'use warnings' as well. They all help
Owen
------------------------------
Date: Tue, 16 Feb 2010 09:58:22 +0000
From: RedGrittyBrick <RedGrittyBrick@spamweary.invalid>
Subject: Re: use strict...
Message-Id: <4b7a6c42$0$2481$db0fefd9@news.zen.co.uk>
On 16/02/2010 03:06, Robin wrote:
> I know this is a pretty stupid question, maybe, but is it better to
> use strict?
Yes. I try to make all my (multi-line) programs start
#!/usr/bin/perl
use strict;
use warnings;
> I have never gotten a concise answer to this question
> because there reallty isn't any docs on it.
The subject is discussed in this newsgroup surprisingly often.
There seems to be a strong consensus for strict and warnings. There is a
respected minority (possibly just one) who argue that `-w` is better
than `use warnings`. Unless you have read and understood the discussion
(and how it applies to your current project) you should 'use warnings'.
------------------------------
Date: Tue, 16 Feb 2010 02:14:56 -0800 (PST)
From: "Patrick H." <patrickh@gmail.com>
Subject: Re: use strict...
Message-Id: <4f04fe05-2ee8-4a79-9ae1-06b520cff31b@z11g2000yqz.googlegroups.com>
On Feb 15, 9:06=A0pm, Robin <rob...@cnsp.com> wrote:
> I know this is a pretty stupid question, maybe, but is it better to
> use strict?
I like it because it makes me be constantly aware of scope since I
have to consciously define everything somewhere. That can only help as
your program code gets longer.
Patrick
------------------------------
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Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V11 Issue 2819
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