[11641] in Perl-Users-Digest
Perl-Users Digest, Issue: 5241 Volume: 8
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Sat Mar 27 19:07:21 1999
Date: Sat, 27 Mar 99 16:00:21 -0800
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, 27 Mar 1999 Volume: 8 Number: 5241
Today's topics:
Re: :t/85s*) 8j.F59%~<F=F;s <koehler@nm-us.campuscwix.net>
Re: a problem.. <gellyfish@gellyfish.com>
Re: combine multiple files into one <gellyfish@gellyfish.com>
Re: Compiling Perl Scripts <cassell@mail.cor.epa.gov>
Re: dumping db header row before display <cassell@mail.cor.epa.gov>
File isn't locked, but Perl says it is? sstarre@my-dejanews.com
Re: Help - Perl the basics <cassell@mail.cor.epa.gov>
Re: Help - Perl the basics <gellyfish@gellyfish.com>
Re: Help! How scanf() in Perl? <cassell@mail.cor.epa.gov>
Re: HELP! Can't get system() to work in DOS/Win3 <gellyfish@gellyfish.com>
Initializing an array with STDIN (newbie) <fairfiel@dundee.net>
Re: internal server error <debot@xs4all.nl>
Re: Missing a module? <gellyfish@gellyfish.com>
Re: Need automatic forwarding perl script <silver+web@wirebird.com>
Re: Newbie cgi DBM help needed <cassell@mail.cor.epa.gov>
Re: Newbie ques., clearing an array <aqumsieh@matrox.com>
Re: Newbie ques., clearing an array <gellyfish@gellyfish.com>
Re: PROBLEM reading file in array <dave_illini@yahoo.com>
Question on how perl launches processes <bomr@lin01.triumf.ca>
Re: Split with + , but no %2B (brian d foy)
Re: Split with + , but no %2B <debot@xs4all.nl>
Re: want to learn about refs? Was: How do you use a var <aqumsieh@matrox.com>
Re: Want to learn Perl <cassell@mail.cor.epa.gov>
Re: Webspace? <cassell@mail.cor.epa.gov>
Re: Webspace? <gellyfish@gellyfish.com>
Re: Where to start with Perl <cassell@mail.cor.epa.gov>
Re: Why don't wildcards expand on cmd line- win32 v5.00 <gellyfish@gellyfish.com>
Re: Writing isn't working, and the mode is set, Help! <aqumsieh@matrox.com>
Re: Writing isn't working, and the mode is set, Help! <gellyfish@gellyfish.com>
Special: Digest Administrivia (Last modified: 12 Dec 98 (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Sat, 27 Mar 1999 16:35:44 -0700
From: "Rick Koehler" <koehler@nm-us.campuscwix.net>
Subject: Re: :t/85s*) 8j.F59%~<F=F;s
Message-Id: <7djq0n$gfb$1@news.campuscwix.net>
Bob Trieger wrote:
>In article <36fade3c.0@ruby.hknet.com>, "$p$p&L%J" <IA'r&n3%> wrote:
[snipski]
>>*l.I%g&3(GCh:C +a(S*>9D7spassword +a $@$A%?1` +K(S&3%h2z7|
>
>>> snippety <<
>
>What we have here folks is the 1999 obscure code winner, hands down!
No, actually, the poster forgot to set "Visp" to ,d{schmengie}. and in
addition, "S&3's'o'Z*:" won't work without deref-ing "&3's'o9L" first.
Typical newbie error, caused by not reading perldoc.
But, we have to agree that using "&30]CD" in this manner is a stroke
of pure genius; I think the poster has a great future in perling.
I would have probably tried to "GCu:C +a(S*>9Q7fcnffjbeq " instead,
and been left wondering what went wrong. (See perldoc CQ%X$#*~
for a good explanation of all this)
------------------------------
Date: 27 Mar 1999 20:37:33 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: a problem..
Message-Id: <7djfid$1ns$1@gellyfish.btinternet.com>
On Sat, 27 Mar 1999 17:35:19 GMT pyjamas wrote:
> whenever i run my perl...
> it shows this to me...
>
> ----
> perl: warning: Setting locale failed.
> perl: warning: Please check that your locale settings:
> LC_ALL = (unset),
> LC_CTYPE = "iso_8859_1",
> LANG = "unset"
> are supported and installed on your system.
> ---
>
> how to solve this?
Of course the warning message does actually contain the information
required to solve it ... however you might also want to read the perllocale
manpage for more on this and possibly also any local man pages on your
systems locale handling ...
for instance on my system there is locale(7) that is most effusive on the
subject. Try for instance a:
gellyfish@gellyfish:/home/gellyfish > man -k locale
I18N::Collate (3pm) - compare 8-bit scalar data according to the current locale
locale (3pm) - Perl pragma to use and avoid POSIX locales for built-in operations
locale (5) - Describes a locale definition file
locale (7) - Description of multi-language support
perllocale (1) - Perl locale handling (internationalization and localization)
setlocale (3) - set the current locale.
strcoll (3) - compare two strings using the current locale
XSetLocaleModifiers (3x) - determine locale support and configure locale modifiers
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: 27 Mar 1999 21:22:10 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: combine multiple files into one
Message-Id: <7dji62$1p6$1@gellyfish.btinternet.com>
On Sat, 27 Mar 1999 08:15:35 -0800 Mei wrote:
> Hello,
>
> I have a few hundred of text files that contain the same format of data.
> Each one of them is very short (~ 5 lines).
>
> I need to combine them into one text file then do some processes from there.
> I have copied and pasted some of them already, but I felt very boring in the
> process.
>
> Somebody suggested me to write a perl script to do it, because it is likely
> I will have a lot more this kind of files been generated each week. I have
> very limited knowledge in perl, could some one help me with the script?
>
Of course on Unix you dont need to anything complicated :
% cat *.txt >blah.out
is sufficient.
Or if you must use Perl :
% perl -e 'print while <> ;' *.txt >blah.out
I seem to recall that there was a longer thread about this quite recently
which you might be able to find via Dejanews.
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: Sat, 27 Mar 1999 14:34:09 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: Compiling Perl Scripts
Message-Id: <36FD5CE1.A3B75CFB@mail.cor.epa.gov>
Peter Sergeant wrote:
> If I've written a Perl Script in a Win95 or Dos version of Perl, is there
> any program I can get to compile it as an EXE that will work on any
> computer?
If you want it to run on *any* computer, then you wouldn't want to
compile it. If your program runs on Win95, then [unless you have used
some Win32-specific features] it should run with minimal alterations
on any platform that has Perl installed already. If you have used
system() or backticks, then you can assume you have made it OS-specific.
If your objective is to be able to run your program on another Win32
box which doesn't have Perl installed, you might consider perl2exe.
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: Sat, 27 Mar 1999 14:09:40 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: dumping db header row before display
Message-Id: <36FD5724.CB491D3@mail.cor.epa.gov>
tlcora wrote:
>
> <posted to comp.lang.perl.misc w/copy e-mailed to respondent>
>
> if $.>1
> did the trick David and thanks for not leaving me hanging!
You're welcome. It's nice to see your kind of response.
> Sam's response (which was appreciated), posted within minutes of my original
> request, was a bit too vague (or I'm just too dense). The only indexed
> reference in the Camel book to ignore is on pg 339 under "Cooperating with
> other processes" which I quickly determined was not what I was looking for.
> Little on 'ignore' in the faqs either. Subsequent searches (including
> ignore) of the archives led me down the 'unless' path. I tried several
> variations, but instead of getting it to ignore only the first line, it
> always ignored everything in $fields ( I don't have a firm enough grasp on
> the language yet).
Frankly, I saw Sam's response later, and thought it was better than mine.
Take a look at p. 530 in the Camel, under "Frequently Ignored Advice".
That may be all the help you need, since you seem to be a self-starter.
> Don't let anyone tell you that you simply did my work for me. Through your
> response, I now know $., $INPUT_LINE_NUMBER, $NR and a lot more about Global
> Special Variables. While I have a copy of the Camel book, I only use it for
> reference (I actually did try to read it, but for some reason, the contents
> only start to make sense to me when I try to apply what I've read and I can
> never seem to find the time or ambition to study simply for the sake of
> studying - yes, I know I suffer because of this).
>
> Yes, you gave me a fish, but I didn't just take the fish and eat it. After
> tasting the fish, I studied it to see how I could catch similar fish. The
> additional advice was a nice bonus too :).
Glad I could whet your appetite.
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: Sat, 27 Mar 1999 22:24:03 GMT
From: sstarre@my-dejanews.com
Subject: File isn't locked, but Perl says it is?
Message-Id: <7djlpu$mfd$1@nnrp1.dejanews.com>
Someone please tell me what airhead I am and point out a bug? I'm almost
desperate enough to write this is c - ICK!
I've been struggling with what I suspected was a locking problem now for
weeks. I added a logging feature that told me when a file was updated, and
how many lines were in the file before & after the update. Here is a snippet
of that log:
Sat Mar 27 15:24:48 1999: start-del 7856 (user1@hotmail.com)
Sat Mar 27 15:24:48 1999: start-del 7856 (user2@hotmail.com)
Sat Mar 27 15:24:52 1999: end-del 5378 (user1@hotmail.com)
Sat Mar 27 15:24:54 1999: end-del 5378 (user2@hotmail.com)
^2500 lines vanish!
User 1 started to delete his record at the same time as user 2. After both of
these deletes took place, 1 record should have been removed from the
sequential file. Instead, OVER 2,000 were removed! Isn't THAT a nice result?
What should have happened was:
User 1 locks the file, copies it to a temp file minus his record, then copies
it back..
User 2 gets a message that says "you cant lock this file".
Instead, some concurrent update takes place that clobbers the file. The lockF
and lockT procedures should have errored if a lock wasn't possible, so
apparently Perl is allowing 2 users to "exclusively" lock this file.
Ths code works fine 99% of the time, except when users collide as in this
case.
****************************************************************************
Here is the code that does the delete (called using memdel("thismem") )
sub memdel # delete the member line, return 1 if deleted
{memlog("start-del",$_[0]);
sysopen(F,$MEM,O_RDWR) || pmessage::SayError("file", "old member file $!");
sysopen(T,$T,O_RDWR|O_CREAT|O_TRUNC)
|| pmessage::SayError("file", "new member file $!");
lockF(0);
lockT(0);
my @profile;
my $f=0;
my $l;
while (<F>)
{$l=$_;
@profile = split(/::/);
$_ = $profile[6];
if ($_ ne $_[0]) {print T $l;} else {$f = 1;}
}
# now erase the original mem file and copy the temp file to it
seek F,0,0;
truncate F,0;
seek T,0,0;
while (<T>)
{print F;}
close T;
close F;
unlockF();
unlockT();
memlog("end-del",$_[0]);
return $f;
}
sub lockF #arg is share
{my $r;
if ($_[0])
{$r=flock(F, LOCK_SH) ||
pmessage::SayError("file", "lock- could not shlock F, try again");}
else
{$r=flock(F, LOCK_EX) ||
pmessage::SayError("file", "lock- could not exlock F, try again");
}
return $r;
}
sub lockT #arg is share
{my $r;
if ($_[0])
{$r=flock(T, LOCK_SH) ||
pmessage::SayError("file", "lock- could not shlock T, try again");}
else
{$r=flock(T, LOCK_EX) ||
pmessage::SayError("file", "lock- could not exlock T, try again");
}
return $r;
}
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
------------------------------
Date: Sat, 27 Mar 1999 15:16:59 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: Help - Perl the basics
Message-Id: <36FD66EB.D57BE7B7@mail.cor.epa.gov>
Stephen Dishon wrote:
> I'm at a loss.
>
> I've programmed in Pascal and lately Java and I am trying to learn Perl. I,
> however, am having problems. I do have a book "Perl5 Complete" which covers
Oh. Now I know why you're at a loss. Get a better book. O'Reilly has
a Learning Perl on Win32 book which is better.
> every operating system known to man...thus is difficult to weed out the
> relevant information. So a few simple questions.
>
> Using Windows 95
This can introduce a problem or two as well. Be aware that Perl comes
with lots and lots of online documentation, but it is somewhat
unix-centric. But see my answer to your question #2.
> 1) Is there a specific package to enter the code in or will notepad
> do...saving the code as <filename.p>
Notepad will do. I've grabbed one of the freeware programming editors
off the net, and it lets me submit the program from within the editor.
A time-saver for me, since I make plenty of typos. On Win32 boxes,
I usually save the program as whatever.pl instead of .p for an extension.
Be sure to use the -w flag when you run your programs.
> 2) Must I have a C compiler to compile Perl in Win95.
If you really want to go through the exercise of downloading source
code and building your own, you will need a C compiler. But you can
just go to www.activestate.com amd get the latest version of Perl,
all ready for installation. It even has the Win32 InstallWizard
features for extra niftiness. And then you can either read the
extensive documentation in html form or using 'perldoc' from a command
window.
> Answers to these question would be most appeciated, with more questions to
> follow.
Since your e-mail address seems to be clean of 'NOSPAM' inserts, you'll
also get an e-mail full of more helpful info. Use the docs, Luke.
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: 27 Mar 1999 21:40:54 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: Help - Perl the basics
Message-Id: <7djj96$1pj$1@gellyfish.btinternet.com>
On Sat, 27 Mar 1999 17:21:00 -0000 Stephen Dishon wrote:
> I'm at a loss.
>
> I've programmed in Pascal and lately Java and I am trying to learn Perl. I,
> however, am having problems. I do have a book "Perl5 Complete" which covers
> every operating system known to man...
I very much doubt it - there is no port of Perl for the ENIAC emulator or
indeed VME,Dragon/OS,Concurrent-DOS,Windows CE, EPOC 32, GEOS blah blah ...
> thus is difficult to weed out the
> relevant information. So a few simple questions.
>
> Using Windows 95
>
> 1) Is there a specific package to enter the code in or will notepad
> do...saving the code as <filename.p>
>
Yes you can use any editor that will save the files in straight text.
Before the inevitable boring thread starts about peoples favoured
editors may I suggest that you check out:
http://reference.perl.com/query.cgi?editors
Where you will find described a number of editors suitable for programmers.
> 2) Must I have a C compiler to compile Perl in Win95.
>
Er no - you can download a precompiled Perl distribution from:
http://www.activestate.com/ActivePerl/
Perl, whilst compiled internally, can be thought of as an interpreted
language in some ways - that is to say you generally do not produce
binary platform dependant object files. Of course some will point you
at various so-called compilers (which are infact nothing of the sort) but
there is no advantage to these if you have the "interpreter" available.
> Answers to these question would be most appeciated, with more questions to
> follow.
>
At this stage I would like to exhort you to read the most wonderful
documentation that comes with the Perl distribution - it *does*
contain the answers for virtually any question that you are likely to
want to ask and many more that you wont think of besides.
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: Sat, 27 Mar 1999 14:28:04 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: Help! How scanf() in Perl?
Message-Id: <36FD5B74.FEE5BE09@mail.cor.epa.gov>
Les Neste wrote:
> Hi friends,
> I'm relatively new to Perl but seem to have reached critical mass for
> writing useful code. Still one thing I haven't seen, though: is
> there a way to get the same functionality as C provides through
> scanf()? I can figure out how to get the same result, but I end up
> having to write a lot of case-specific code, and I wonder whether Perl
> provides a general-purpose solution?
Perl doesn't have an exact duplicate of C's scanf(). But it doesn't
need one. Read up on what you can do with split(), or with a regex,
or even with unpack(). Learning Perl might be a good start, although
if you're already fluent in C you might find Programming Perl more
your speed. Use 'perldoc -f function-name' to read about the functions,
and 'perldoc perlre' to read about regexen, and 'perldoc perlop' to
learn about using regexes in Perlish ways (among other things).
Good luck, and in the words of Larry Wall, "Have the appropriate
amount of fun."
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: 27 Mar 1999 20:58:28 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: HELP! Can't get system() to work in DOS/Win3
Message-Id: <7djgpk$1o2$1@gellyfish.btinternet.com>
On Sat, 27 Mar 1999 10:58:31 -0500 Dave Abramowitz wrote:
> I'm sitting here at a "customer" site, trying to get simple system commands
> to work under DOS, specifically system("pause") and system("cls"). They
> don't work.
I'm not going to boot this bugger back into DOS for this (does it still
work ?) but I think you will find that the commands that you cite are
command interpreter internals and as succh you will need to run them as
system("command /c cls");
for instance.
Anyhow both of those commands could equally well be handled in pure Perl
I reckon - again I'm not going to relinquish my machine to the evil-empire
to find out though.
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: Sat, 27 Mar 1999 17:30:17 -0500
From: Sender <fairfiel@dundee.net>
Subject: Initializing an array with STDIN (newbie)
Message-Id: <36FD5BF9.C5EE23B0@dundee.net>
Hello
If the answer to my question is anywhere in the llama book, just say
where!
I've been trying to place an input file into an array, and then split()
that array. I get messages indicating that the array is not initialized:
"Use of implicit split to @_ is deprecated," and "Use of uninitialized
value at line xxx, <INFILE> chunk xxx."
I've tried a few approaches:
1. Use a loop to read each line from the text file into the array. Use
the split() function after each line is read in, or after the whole
array has been (supposedly) filled.
2. Put the data file directly into the array:
@order = <INFILE>; (With variations in syntax).
ANy help/hints/answers are greatly appreciated.
TIA,
New guy
fairielATdundeeDOTnet
------------------------------
Date: Sat, 27 Mar 1999 23:57:00 +0100
From: Frank de Bot <debot@xs4all.nl>
Subject: Re: internal server error
Message-Id: <36FD623C.C65A8120@xs4all.nl>
You must chmod them 755.
Lars Plessmann wrote:
> I create my perl scripts in windows. The are running without any problem
> on my Sambar Server 4.1
> When I trie to execute them on Linux, there is an error message
> "internal server error". What's wrong with my perl script? I think I
> changed the attributes in a correct way (chmod 777 file.pl)
>
> Please, help me!
>
> ps: If you've got an answer, please mail it to this forum and to me:
> larsplessmann@gmx.de
> thx!
------------------------------
Date: 27 Mar 1999 23:31:43 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: Missing a module?
Message-Id: <7djpov$1th$1@gellyfish.btinternet.com>
In comp.lang.perl.misc melLA@west.net wrote:
> While trying to run Makefile.PL on module DBI, at the command line I
> typed:
>
> perl5.00502 -w Makefile.PL prefix=/home/user/.../.../cgi-bin/perl/lib
>
> and I got back:
>
> Can't load module IO, dynamic loading not available in this perl.
> (You may need to build a new perl executable which either supports
> dynamic loading or has the IO module statically linked into it.)
>
> Am I missing a module? I would think the latest Perl would feature
> dynamic loading if it were needed.
>
No. On some platforms, most notably SCO unix in my experience, Perl will
by default be built with static linking and therefore any further modules
that require to use dynamic loading will not work - there are two options
both of which require rebuilding your perl : rebuild your perl with the
required module statically linked in - this is available at the time of
running configure - I think that you will probably have to monkey with
some of the configuration files in order to create a makefile that will
link the extension statically.
Alternatively you can attempt to build a dynamically linked perl - this will
almost certainly require you to compare the compiler and linker switches
being used in the makefiles with those that would induce dynamic linking
as described in the documentation of your compiler. You will need then
to supply those flags as necessary when asked by the configure script. If
the build fails you may need to manually alter config.sh and run Configure -S
to propagate those changes.
If indeed you are on a SCO platform then fortunately part of this process
for building a dynamic perl is documented somewhere on their skunkware site
- I cant remember ( or can be bothered right now to find out :) the URL
but its fairly obvious once you get going.
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: 27 Mar 1999 22:37:31 GMT
From: Karen J. Cravens <silver+web@wirebird.com>
Subject: Re: Need automatic forwarding perl script
Message-Id: <8D96A9754phoenyx@news.southwind.net>
"Beny Spensieri" bernardino.spensieri@utoronto.ca wrote in
<36FD1EE7.D2C0F627@utoronto.ca>:
> I need a script that will forward a user to another page after a
> few seconds. This is commonly used to send web serfers to the
> new location of a web page that has moved.
Scripts aren't needed for that; simply put
<META HTTP-EQUIV="refresh" CONTENT="5; URL=http://newurl">
in the HTML, somewhere between <HEAD> and </HEAD>. (Replace the 5 with
the number of seconds you want to delay.)
Doesn't work with all browsers, hence the usual "If your browser doesn't
automatically take you, click here" link also found on such pages.
------------------------------
Date: Sat, 27 Mar 1999 14:49:19 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: Newbie cgi DBM help needed
Message-Id: <36FD606F.D2BAC159@mail.cor.epa.gov>
Thomas J. Margolis wrote:
> Hello all,
> I'm new to Perl5 (Perl4 is already my friend) and I want to...
> 1.) Learn how to "upgrade" Perl4 to Perl5 in my brain;
Programming Perl, the turquoise version. Twice as thick,
twice as good. And the online docs that come with Perl5 are
pretty good too. Start with 'Previous Perl Traps', and then
look up anything you see which makes your brain go sproing.
> 2.) Learn how to find, install, and use a DBM module;
Check out CPAN for all things modulous. DBI / DBD now
has a front end which insulates the programmer from the
specific RDBMS, so you can (in theory) use the same code to
access an Oracle database or MySQL.
> 3.) Learn how to use Perl5 to interact with databases.
Start with #2 and read the docs.
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: Sat, 27 Mar 1999 16:47:25 -0500
From: Ala Qumsieh <aqumsieh@matrox.com>
To: ncherry@home.net
Subject: Re: Newbie ques., clearing an array
Message-Id: <x3yiubmvc43.fsf@tigre.matrox.com>
[posted and emailed]
njc@dmc.uucp (Neil Cherry) writes:
> I have 2 books on Perl and I find the arrays the most confusing part.
Which two books are they? Arrays are basic structures, and should be
the among the simplest "parts". You should check the 'perldata'
documentation which comes with the standard Perl distribution, and
should be installed on your system (if Perl was properly installed
that is). Simply type:
% perldoc perldata
in a window, and you should get the docs.
> Actually I have 2 questions:
>
> 1) How does one clear an array after it's bee filled?
undef @array;
or
@array = ();
or
$#array = -1;
or
splice @array, 0;
or
shift @array while @array;
or
pop @array while @array;
That's as many ways as I can think of at the moment. Do you want more?
> 2) How does one create a multi dimension array or an array of structures?
Think references. You can't create multi-dimensional arrays in
Perl. But you can create arrays of references to arrays. Just like a
string in C is an array of pointers to characters. The best starting
point would be the 'perldsc' (Perl Data Structures Cookbook)
documentation which should also be installed on your system. Read it
and enjoy.
HTH,
Ala
------------------------------
Date: 27 Mar 1999 21:03:32 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: Newbie ques., clearing an array
Message-Id: <7djh34$1ot$1@gellyfish.btinternet.com>
On Sat, 27 Mar 1999 16:13:03 GMT Neil Cherry wrote:
> I have 2 books on Perl and I find the arrays the most confusing part.
>
You obviously havent been trying too hard then ;-}
> Actually I have 2 questions:
>
> 1) How does one clear an array after it's bee filled?
>
Clear in what way ?
$#array = -1;
@array = ();
shift @array while $#array;
I could go on getting increasingly incorrect.
> 2) How does one create a multi dimension array or an array of structures?
>
Probably best to read the docs on this one as it is quite a wide and varied
subject:
perldoc perllol
perldoc perldsc
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: Sat, 27 Mar 1999 16:59:39 -0600
From: David <dave_illini@yahoo.com>
Subject: Re: PROBLEM reading file in array
Message-Id: <36FD62DA.C5264EA9@yahoo.com>
This may help you. This subroutine reads a txt file, ignores any
commented or blank lines,
then gets rid of any whitespace before a word, and then places the one
word per line into
the array @text_read. Then @text_read is returned and becomes
@arrayfromfile.
I use this to have store long lists that may change (such as server names
or key search words)
in a seperate file from my main code. That way I can allow others to
change the list file, but not touch my codefile.
To allow an entire text line with many words, insert these changes
into the code below
$temp=~(s/^\s+//) if $temp=~/^\s+/;
>From David
@arrayfromfile=(&readfromfile);
#This sub reads the file cutfirst and stores the non-commented, 1 string
per line,
#values into the array @cutouts. If there are 2 or more words on an
uncommented line,
#the program dies. It removes white spaces before words and cuts the
carriage returns
#before writing to cutouts array
sub readfromfile
{
open(FILE_TO_READ,"+<any_text_file");
local($uncommented_lines_read=0);
local(@text_read=());
while(<FILE_TO_READ>)
{
if((!/#/)&&(/\w/)) #ignores commented or blank lines
{
local($temp)=$_;
#removes carriage return so it won't be placed into the array
chomp $temp;
###Your changes go here
$temp!~(m/(^\w)(\s)/) || die "Error: Use only one word per line in the
file youre reading!\n";
#gets rid of leading white spaces
$temp=~(s/^\s+//g) if $temp=~/^\s+/;
###End your changes
$text_read[$uncommented_lines_read]=$temp;
$uncommented_lines_read++;
}
}
close FILE_TO_READ;
return @text_read;
}
Zenno wrote:
> Hello all,
>
> I am trying to read in a textfile in an array so that
>
> FILE.TXT
> line1
> line2
> line2
>
> becomes
>
> @array = (line1,line2,line3)
>
> My code is:
> ...
> (code for opening file etc)
> ...
>
> while (<EMAILADDRESSES>) {
> $tmp = chomp; #get rid of newline char
> push(@Subscribe_EMail_Data, [@tmp]); #add line as reference to list
> print "-" . $Subscribe_EMail_Data . "<BR>";
> }
> ...
>
> (code for closing file and returning array)
>
> But all the print statements prints is lines containing '-'
>
> What am I doing wrong here?
>
> please cc to zmbakker@xs4all.nl
>
> Thanks!
------------------------------
Date: 27 Mar 1999 22:50:44 GMT
From: "Rod B. Nussbaumer" <bomr@lin01.triumf.ca>
Subject: Question on how perl launches processes
Message-Id: <7djnc4$nc8$1@nntp.ucs.ubc.ca>
Perl Gurus:
I am not sure this is completely a perl question, but since it
arises in the context of a perl progamming exercise, I will ask
it.
I am attempting to open a file, by piping the ouptput from
the 'ps' program into my perl file, like this (excuse typos,
this is from memory):
$Status = open( PSOUT, "/usr/bin/ps -agluwx |" );
This is being done on a Solaris machine, which has two versions
of ps, each behaving differently, and both taking different
command line args.
Now, from my tcsh command line, I can execute the above ps
command line, and it behaves exactly as I expect. When I
invoke it from the perl script (either executed as a script
starting with '#!/usr/bin/perl', or by running 'perl pstest.pl'),
it always finds the other version of ps, even though I
specify the complete filespec, including the absolute path to
the the program. There are no links to other points in the file
system involved.
>From tcsh, I cannot seem to invoke the 'other' version of ps.
If I invoke a Bourne shell, the same behavior exsists as the
perl script exhibits. So, perhaps I don't understand the rules
about how programs are located by the interpretters, perl and sh.
Can someone please clarify this for me? I will soon have this
piece of code installed in a production setting, and would be
a lot happier if I knew what was causing the behavior I am seeing.
Thanks,
--- rod.
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Rod Nussbaumer, Programmer/Technologist Internet: bomr@triumf.ca
TRIUMF --- University of British Columbia, Phone: (604)222-7449
Vancouver, BC, Canada. FAX: (604)222-7307
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
------------------------------
Date: Sat, 27 Mar 1999 17:08:51 -0500
From: comdog@computerdog.com (brian d foy)
Subject: Re: Split with + , but no %2B
Message-Id: <comdog-ya02408000R2703991708510001@news.panix.com>
In article <36FD477E.D90081AD@xs4all.nl>, Frank de Bot <debot@xs4all.nl> posted:
> Is there anyway to split a string with + while %2B stays ?
@list = split /\+/, $string;
i'm trying to think how you are doing it so that there is a
problem...
--
brian d foy
CGI Meta FAQ <URL:http://www.smithrenaud.com/public/CGI_MetaFAQ.html>
------------------------------
Date: Sat, 27 Mar 1999 23:52:51 +0100
From: Frank de Bot <debot@xs4all.nl>
Subject: Re: Split with + , but no %2B
Message-Id: <36FD6143.2235FC45@xs4all.nl>
%2B is + in the Query string. The way you say doesn't work.
brian d foy wrote:
> In article <36FD477E.D90081AD@xs4all.nl>, Frank de Bot <debot@xs4all.nl> posted:
>
> > Is there anyway to split a string with + while %2B stays ?
>
> @list = split /\+/, $string;
>
> i'm trying to think how you are doing it so that there is a
> problem...
>
> --
> brian d foy
> CGI Meta FAQ <URL:http://www.smithrenaud.com/public/CGI_MetaFAQ.html>
------------------------------
Date: Sat, 27 Mar 1999 16:05:01 -0500
From: Ala Qumsieh <aqumsieh@matrox.com>
Subject: Re: want to learn about refs? Was: How do you use a variable in an array name?
Message-Id: <x3ylngive2q.fsf@tigre.matrox.com>
tice@hunch.zk3.dec.com (Walter Tice USG) writes:
> I've never been a big fan of the perldsc, finding it somewhat opaque
> compared to most of the perldoc.
Could you point out specific areas that need to be clarified/rewritten?
I believe a patch is always welcome.
PS. Personally, I like perldsc the way it is. Greater detail never
hurts though.
Ala
------------------------------
Date: Sat, 27 Mar 1999 14:18:38 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: Want to learn Perl
Message-Id: <36FD593E.ECF54450@mail.cor.epa.gov>
ICG's wrote:
> In article <slrn7fe7j8.6eo.sholden@pgrad.cs.usyd.edu.au>, sholden@cs.usyd.edu.au wrote:
> >On 23 Mar 1999 03:29:21 GMT, ICG's <postmaster@uu.net> wrote:
> >>
> >>At first, I hated the concept of Java. But it's usefull for neat little
> >>tricks that are impossible in Perl. Perl on the other hand, can do things
> >>that Java can't do. (such as fingering 3 separate network access servers,
> >>doing a selective port scan across 15 IPs, manipulating the data and telling
> >>you the state of all the critical systems and services in an ISP, and the
> >>number of users <with logon names>)
> >
> >That is possible in Java, it might need a little more code but it is possible.
> >
>
> Ahh, that's the catch. 200 or so lines (or less, I included comments) of
> Perl. My pref is a good load time. The bad part about the script is you have
> to wait for the other servers to answer up. It's sort of a trade off. Spit
> the Java enhanced HTML out to the client, and have the client do the querying,
> or do it locally (maintaining some of the integrety of the servers by not
> giving out un-neccessary info), and returning the results.
Granted that Java does have its uses, but it wouldn't surprise me if
a Perl-win32 expert (Dave Roth or Jenda, for instance) could whip out a
better Perl solution in far less than 200 lines. I find that the trouble
most people have in comparing solutions in different languages is that
they are good in one or two of their choices and weaker than they realize
in the others. Most of the Perl-Java and Perl-Python comparisons I have
seen seem to fall into this trap. But that doesn't mean that you're not
right in your example. I like Perl, but I don't pretend that it is a
panacea for all programming ills.
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: Sat, 27 Mar 1999 15:05:46 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: Webspace?
Message-Id: <36FD644A.3B4B598C@mail.cor.epa.gov>
editor@dvar.com wrote:
> Hi everybody,
> Who knows what is reguired (software & expenses) to setup a server with
> 18 giga harddisk.
> I know nothing so all info on this are welcome.
> Thanking you in anticipation
I'm sorry, but this is really the wrong newsgroup to be asking.
Even if you want to set up a webserver and run Perl programs on it,
this is still the wrong newsgroup.
If you already have the hardware and OS, ask in one of the many, many
OS-specific newsgroups. If you do not even have the OS selected yet,
then you'll want to spend some time reading newsgroups and documents
to decide which OS and webserver and web authoring software you
would prefer.
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: 27 Mar 1999 20:30:09 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: Webspace?
Message-Id: <7djf4h$1m8$1@gellyfish.btinternet.com>
On Sat, 27 Mar 1999 15:18:00 +0100 editor@dvar.com wrote:
> Hi everybody,
>
> Who knows what is reguired (software & expenses) to setup a server with
> 18 giga harddisk.
>
> I know nothing so all info on this are welcome.
>
Sorry old chap but this really really aint anything to do with Perl -
OK I guess you gotta have a machine to run a perl on but hey you've
got one to send a message to this group and beleive me *that* machine is
enough ...
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: Sat, 27 Mar 1999 15:23:26 -0800
From: "David L. Cassell" <cassell@mail.cor.epa.gov>
Subject: Re: Where to start with Perl
Message-Id: <36FD686E.61CD4259@mail.cor.epa.gov>
richb@ezl.com wrote:
> I learned Perl by reading the book "Learning Perl" by Randle Schwartz and
> worked all the examples. Then I bought "Perl in a Nutshell". Two very good
> books. If you have programmed in C, you won't have a problem picking it up.
> I was a REXX programmer in a previous life and I've programmed in C and C++.
> Perl makes things much easier to do than any other language I've used. Good
> Luck! Rich
s/Randle/Randal/
Unless this is a new bit of jargon I haven't heard.
Maybe RANDom filehandLE ?
David
--
David L. Cassell, OAO cassell@mail.cor.epa.gov
Senior computing specialist
mathematical statistician
------------------------------
Date: 27 Mar 1999 22:12:40 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: Why don't wildcards expand on cmd line- win32 v5.005_02
Message-Id: <7djl4o$1qo$1@gellyfish.btinternet.com>
On Tue, 23 Mar 1999 14:16:27 GMT Bart Lateur wrote:
> Michael P McGill wrote:
>
>>Why do I get the message:
>>"Can't open *.log: No such file or directory"
>>
>>from the following command line:
>>"C:\Data>perl chk_log.pl *.log"
>
> Are there any *.log files? I noticed in DJPerl on DOS that if there is
> no file matchiung the wildcard, thze wildcard isn't expanded (to
> nothing). Could be the case here, too.
>
Bearing in mind that it can appear like that on 'proper' shells too:
gellyfish@gellyfish:/home/gellyfish > cat *.baz
cat: *.baz: No such file or directory
gellyfish@gellyfish:/home/gellyfish > echo $SHELL
/bin/bash
So it would appear that 'bash' will pass the unexpanded pattern on as well
if there is no match - I cant say whether this is an officially sanctioned
behaviour though.
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: Sat, 27 Mar 1999 16:38:08 -0500
From: Ala Qumsieh <aqumsieh@matrox.com>
Subject: Re: Writing isn't working, and the mode is set, Help!
Message-Id: <x3yk8w2vcjk.fsf@tigre.matrox.com>
"William Flanagan" <wflanagan@msn.com> writes:
> #!c:\progra~1\perl\bin\perl
You definitely need a '-w' up there, especially that you are having
problems writing the code. It will trigger a lot of warnings I'm sure.
> # This is my first attempt at writing a program that will convert my Notes
> database to a comma delimited
> # file. This takes any structured text file and converts it to comma
> delimited.
> # Function: Reverse each line of a file
>
> #-------
> # Step Number 1: Get command line values:
> #-------
>
> if ($#ARGV !=1) {
> die "Structured Text to Comma Delimiter, 1999 William Flanagan\n Usage:
> $0 inputfile outputfile\n";
> }
> ($infile,$outfile) = @ARGV;
> if (! -r $infile) {
> die "Can't read input $infile\n";
> }
> if (! -f $infile) {
I would use a '_' (underscore) instead of $infile here. It's a shred
faster (nothing significant though in your case).
> die "Input $infile is not a plain text, please use a structured plain
> text file\n";
> }
>
> #-------
> # Step Number 2: Validate files
> #-------
>
> $mode='+<';
> open(INPUT,"+<$infile") ||
This allows you to read from and write to the file.
> die "Can't open $infile successfully, ensure $infile is plain text $!";
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This can't be the problem since you check for that already.
> if ( -e $outfile) {
> print STDERR "Output file $outfile exists!\n";
> until ($ans eq 'r' || $ans eq 'a' || $ans eq 'e' ) {
'-w' will warn you here about the use of the uninitialized variable
$ans.
> print STDERR "replace, append, or exit? ";
> $ans = getc(STDIN);
Any good reason for using getc() here instead of the usual
chomp($ans = <STDIN>);
??
> }
> if ($ans eq 'e') {exit}
> }
> if ($ans eq 'a') {$mode='>>'}
>
> else {$mode='>'}
>
> open(OUTPUT,"$mode$outfile") ||
> die "Can't create $outfile file, ensure that it does not exist $!";
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Again, this is a useless piece of advice. You shouldn't care if the
output file exists or not. It will be created if it doesn't exist.
>
>
> $ccount = 0;
>
> #------
> # Step Number 3: Read input, preprocess, and add to first line arguments for
> output
> #------
>
> while ($line = <INPUT>) {
If you are using an older Perl (pre 5.005), you should test this with
defined():
while (defined($line = <INPUT>)) {
> ($fieldname, $fieldvalue) = split(":", $line);
> if ($fieldname eq '') {
> next;}
Is the above meant to skip empty lines? If it does, then the usual:
next if $line =~ /^\s*$/;
is a better choice.
> chomp($fieldvalue);
> chomp($fieldname);
This is not necessary since $fieldname should NEVER have a $/ at its
end (unless ":" never appears in the line). I would say, just
chomp $line;
before you split it.
> $foundfield='n';
> for ( $a=0; $a <= $ccount; $a++) {
> if ($columnlist[$a][1] eq $fieldname) {
> $foundfield='Y';
> last; }
> }
> if ($foundfield eq 'n') {
> $columnlist[$ccount] = ["$ccount", "$fieldname"];
I really think it's useless to store $ccount in the anonymous hash,
since it's always the same as the array index. But hey, it's your
program.
> print STDOUT "Adding $fieldname to record list.\n";
Does the above line show up as expected?
Also, what about $fieldvalue? You never use it. Are you sure you want to
discard it like that?
> $ccount++;
> }
> }
>
> print STDOUT "\n\nTotal ccount is $ccount.\n";
Obviously, you are worried about multiple entries in your file. You
don't want them. You want only one copy. So, just use a hash. Instead
of the big mess you have, simple do something like:
while (<INPUT) {
next if /^\s$/;
chomp;
($fieldname, $fieldvalue) = split /:/;
$columnlist{$fieldname} = $fieldvalue;
}
> #------
> # Step Number 4: Gather outputfile information
> #------
>
> close INPUT;
Check the return value of your close() the way you do for open().
> open(INPUT,"<$infile") ||
> die "Can't open $infile successfully, ensure $infile was not deleted or
> moved $!";
Hmmm... you close INPUT and re-open it. Did you do this to simply
start over from the beginning of the file?
If so, a simpler (and faster) approach would be:
seek INPUT, 0, 0;
But, the above might be a typo. I think you need $outfile instead of $infile.
> $j=0;
> while ($line = <INPUT>) {
again .. test with defined()
> ($fieldname, $fieldvalue) = split(":", $line);
> chomp($fieldvalue);
> chomp($fieldname);
same as above.
> $foundfield='n';
> if ($fieldname eq '') {
> $eorcount++;
> print STDOUT "\nEnd of Record count number $eorcount.\n\n";
> if ($eorcount eq 3) {
> for ($k=0;$k<=$#recorddata;$k++) {
> select OUTFILE;
what is OUTFILE? It is not an open filehandle. Did you check your
program yourself? Did you write it? Is this the complete thing?
> print "$recorddata[$k]", ", ";
> select STDOUT;
> print "$recorddata[$k]", ", ";
> }
>
> select OUTFILE;
> print "\n";
> select STDOUT;
> print STDOUT "\n";
> @recorddata = ();
> $eorcount = 0;
> next;
> }
> }
> for ( $a=0; $a <= $ccount-1; $a++) {
> print STDOUT "Comparing $fieldname to $columnlist[$a][1].\n";
> if ($columnlist[$a][1] eq $fieldname) {
> @recorddata[$a] = $fieldvalue;
The above will generate a warning under '-w'.
> print STDOUT "Found $fieldname in record, adding @recorddata[$a]
> to record.\n";
> $foundfield='Y';
> $eorcount = 0;
> last;
> }
> }
> if ($foundfield eq 'n') {
> $eorcount++;
> }
> print STDOUT "Moving onto record $j\n\n";
> $j++;
> }
>
>
> #-------
> # 4: Done!
> #-------
>
> close INPUT,OUTPUT;
> exit;
There are way too many errors in your program. You seem to be
confused and your strategy is weird (for me at least :).
Maybe you should try with something a bit simpler
first, like reading from a file, reformatting, and writing to another
file. No need to check for any duplication of data at the moment. Once
you figured out how to do that, you can add various types of sanity
checks into your program.
Try again, and let us know.
HTH,
Ala
------------------------------
Date: 27 Mar 1999 20:53:47 -0000
From: Jonathan Stowe <gellyfish@gellyfish.com>
Subject: Re: Writing isn't working, and the mode is set, Help!
Message-Id: <7djggr$1nv$1@gellyfish.btinternet.com>
On Sat, 27 Mar 1999 10:21:31 -0500 William Flanagan wrote:
> #!c:\progra~1\perl\bin\perl
I'm sure that its been said here before but I think it probably (and
possibly mistakenly) needs to be reiterated - it will end in tears if
you install your Perl in a directory with spaces in the path ...
Anyhow cant Notes output a CSV file ?
/J\
--
Jonathan Stowe <jns@gellyfish.com>
Some of your questions answered:
<URL:http://www.btinternet.com/~gellyfish/resources/wwwfaq.htm>
Hastings: <URL:http://www.newhoo.com/Regional/UK/England/East_Sussex/Hastings>
------------------------------
Date: 12 Dec 98 21:33:47 GMT (Last modified)
From: Perl-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Special: Digest Administrivia (Last modified: 12 Dec 98)
Message-Id: <null>
Administrivia:
Well, after 6 months, here's the answer to the quiz: what do we do about
comp.lang.perl.moderated. Answer: nothing.
]From: Russ Allbery <rra@stanford.edu>
]Date: 21 Sep 1998 19:53:43 -0700
]Subject: comp.lang.perl.moderated available via e-mail
]
]It is possible to subscribe to comp.lang.perl.moderated as a mailing list.
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------------------------------
End of Perl-Users Digest V8 Issue 5241
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