[26115] in Perl-Users-Digest
Perl-Users Digest, Issue: 8311 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Wed Aug 10 14:05:45 2005
Date: Wed, 10 Aug 2005 11:05:09 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Wed, 10 Aug 2005 Volume: 10 Number: 8311
Today's topics:
Re: "anonymous" variable in Perl? (Anno Siegel)
compare and merge <mislam@spam.uiuc.edu>
Re: compare and merge <noreply@gunnar.cc>
Re: compare and merge axel@white-eagle.invalid.uk
Re: Comparing XML files <bart.lateur@pandora.be>
Re: copy contructor (Anno Siegel)
Re: Feed a directory listing to a script (Anno Siegel)
Re: Feed a directory listing to a script <matthew.king@monnsta.net>
Re: Feed a directory listing to a script <joe@inwap.com>
Re: ignore new line for long string (Anno Siegel)
Re: Naive Unix Socket client (Anno Siegel)
Problem in passing values to perl script using another <vikrantREMOVE@DELETEsaysnetsoft.com>
Re: Problem in passing values to perl script using anot <noreply@gunnar.cc>
Re: Problem in passing values to perl script using anot <joe@inwap.com>
Re: Problem in passing values to perl script using anot <vikrantREMOVE@DELETEsaysnetsoft.com>
Re: Simple Question about Scalars <djames@thehub.com.au>
Re: Simple Question about Scalars <vtatila@mail.student.oulu.fi>
Re: Syntax highlighting in perl debugger <mshaw@bangnetcom.com>
Re: talking to a port, and server daemon: partly OT <joe@inwap.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 9 Aug 2005 20:15:33 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: "anonymous" variable in Perl?
Message-Id: <ddb2t5$7c8$5@mamenchi.zrz.TU-Berlin.DE>
Peter Scott <Peter@PSDT.com> wrote in comp.lang.perl.misc:
> On Thu, 04 Aug 2005 09:04:07 +0000, Anno Siegel wrote:
> > The non-standard
> > module Time::Piece (available from CPAN) does it for you. It overrides
> > localtime() and gmtime() so that they return objects which support
> > appropriate methods.
> >
> > use Time::Piece;
> > my $t = localtime;
> > ( $day, $month) = ($t->mday, $t->mon);
>
> Unnecessary to use a non-standard module:
>
> % perl
> use Time::localtime;
> my ($day, $month) = (localtime->mday, localtime->mon);
> print "$day $month\n";
> ^D
> 8 7
Ah, good to know there's an alternative. I like the functionality of
Time::Piece, but not the implementation.
Anno
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------------------------------
Date: Tue, 09 Aug 2005 16:34:09 -0500
From: Sharif Islam <mislam@spam.uiuc.edu>
Subject: compare and merge
Message-Id: <ddb7g4$tmi$1@news.ks.uiuc.edu>
I am trying to read a text file and compare each line. The sorted
records are separated by '|' and the first field is a number. If the
numbers are same then I will merge the two lines. (I am yet to write the
merge functions). But when I compare the numbers, I am getting '0' when
I should get '-1'. What's wrong?
#!/usr/bin/perl
use strict;
my @raw_data;
while(<DATA>) {
chomp;
push @raw_data, $_; }
my $a=$raw_data[0];
my $b=$raw_data[1];
print "$a\n";
print "$b\n";
my $rv = compare2($a,$b);
# this should return 0 when the numbers are equal.
print "$rv\n";
sub compare2 {
my ($a,$b) = @_;
my ($a1,$a2,$a3) = ($a =~ m!(^\d+)\|(\w*)\|(\w*)! );
my ($b1,$b2,$b3) = ($b =~ m!(^\d+)\|(\w*)\|(\w*)! );
$a1 <=> $b1;
}
__DATA__
1|Population. English selection|1989-2001
2|Journal of social policy|
3|Modern Asian studies|
3|Modern Asian studies|1967-1999
4|Journal of education for teaching : JET|03/1990-Present
4|Journal of education for teaching : JET|1997-2000
4|Journal of education for teaching : JET|1995-Present
5|Journal of geography in higher education|03/1990-Present
5|Journal of geography in higher education|1997-2000
6|British educational research journal|
------------------------------
Date: Tue, 09 Aug 2005 23:51:47 +0200
From: Gunnar Hjalmarsson <noreply@gunnar.cc>
Subject: Re: compare and merge
Message-Id: <3lsmrpF13ij1fU1@individual.net>
Sharif Islam wrote:
> I am trying to read a text file and compare each line. The sorted
> records are separated by '|' and the first field is a number. If the
> numbers are same then I will merge the two lines. (I am yet to write the
> merge functions). But when I compare the numbers, I am getting '0' when
> I should get '-1'. What's wrong?
You need to consider what \w matches in a regular expression. You
probably should replace the occurrences of \w with [^|]
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
------------------------------
Date: Tue, 09 Aug 2005 22:11:25 GMT
From: axel@white-eagle.invalid.uk
Subject: Re: compare and merge
Message-Id: <hS9Ke.41655$FG3.9815@fe3.news.blueyonder.co.uk>
Sharif Islam <mislam@spam.uiuc.edu> wrote:
> I am trying to read a text file and compare each line. The sorted
> records are separated by '|' and the first field is a number. If the
> numbers are same then I will merge the two lines. (I am yet to write the
> merge functions). But when I compare the numbers, I am getting '0' when
> I should get '-1'. What's wrong?
> #!/usr/bin/perl
>
> use strict;
use warnings;
> my @raw_data;
> while(<DATA>) {
> chomp;
> push @raw_data, $_; }
> my $a=$raw_data[0];
> my $b=$raw_data[1];
> print "$a\n";
> print "$b\n";
> my $rv = compare2($a,$b);
> # this should return 0 when the numbers are equal.
> print "$rv\n";
>
> sub compare2 {
> my ($a,$b) = @_;
> my ($a1,$a2,$a3) = ($a =~ m!(^\d+)\|(\w*)\|(\w*)! );
> my ($b1,$b2,$b3) = ($b =~ m!(^\d+)\|(\w*)\|(\w*)! );
Why not use a simple split?
my ($a1,$a2,$a3) = split /\|/, $a;
my ($b1,$b2,$b3) = split /\|/, $b;
This avoids the pitfalls of trying to get a regex which
will match correctly.
> $a1 <=> $b1;
> }
> __DATA__
Axel
------------------------------
Date: Tue, 09 Aug 2005 21:56:52 GMT
From: Bart Lateur <bart.lateur@pandora.be>
Subject: Re: Comparing XML files
Message-Id: <u19if1d0f6cmb5g91r7glu75tr3iose2d5@4ax.com>
Rumpa wrote:
>I have an XML file which has holds actual result. I have another XML file
>which has the expected result. I need to compare these two and see if they
>are the same.
Take a look at the module XML::Diff. It might do what you want.
--
Bart.
------------------------------
Date: 9 Aug 2005 19:42:34 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: copy contructor
Message-Id: <ddb0va$7c8$2@mamenchi.zrz.TU-Berlin.DE>
David Combs <dkcombs@panix.com> wrote in comp.lang.perl.misc:
> In article <dbjq74$jgn$1@mamenchi.zrz.TU-Berlin.DE>,
> Anno Siegel <anno4000@lublin.zrz.tu-berlin.de> wrote:
[Inheritance in Perl]
> >In fact, I think I'll make a (not much) more extensive writeup of this
> >material and put it on the web (at least). The final trick deserves
> >publicity, if I say so myself, but even without it, more awareness of
> >accessors and their significance would help OO programming in Perl.
> >
> >Anno
>
>
> WHERE, WHERE?
>
> WHEN, WHEN?
>
> IF, IF?
>
>
> Thanks from *lots* of people!
I'm working on it, but it's going slow. Some of the problems in Perl OO
don't exist in more mainstream OO languages, so there are no textbooks
to steal from :)
Anno
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------------------------------
Date: 9 Aug 2005 20:00:34 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Feed a directory listing to a script
Message-Id: <ddb212$7c8$3@mamenchi.zrz.TU-Berlin.DE>
[newsgroups trimmed]
Shabam <chalupa@yomama-nospam.com> wrote in comp.lang.perl.misc:
> > > Please don't tell me to just tar/gz the /Users/ directory. That will
> not
> > > work for this because it will be greater than 4GBs,
> >
> > So?
>
> You don't get it do you?
What don't I get? Some file systems have a size limit (usually at 2 GB,
not 4), but others don't. I have built and used backups that were much
larger.
As for your original question, you visit each home directory and run your
backup script on it with an individual output file. That's what thousands
of sysadmins are doing. What's the problem?
Anno
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------------------------------
Date: Tue, 09 Aug 2005 21:37:43 +0100
From: Matthew King <matthew.king@monnsta.net>
Subject: Re: Feed a directory listing to a script
Message-Id: <87hddyluco.fsf@knight.monnsta.net>
"Shabam" <chalupa@yomama-nospam.com> writes:
> My directory structure is like this:
>
> /Users/0/
> /Users/1/
> /Users/2/
> /Users/3/
> ... so on...
>
> User account names reside in those folders, so user jason would be in
> "Users/j/jason".
You don't even need to use perl, you can do this directly in bash:
for k in /Users/*/*/; do run_backup_script "$k"; done
The perl equivalent would look similar but IIRC be a bit mor involved.
Matthew
--
I must take issue with the term "a mere child," for it has been my
invariable experience that the company of a mere child is infinitely
preferable to that of a mere adult.
-- Fran Lebowitz
------------------------------
Date: Tue, 09 Aug 2005 23:42:24 -0700
From: Joe Smith <joe@inwap.com>
Subject: Re: Feed a directory listing to a script
Message-Id: <CrOdneBuO7hEPGTfRVn-2A@comcast.com>
Shabam wrote:
>>> Please don't tell me to just tar/gz the /Users/ directory.
>>> That will not work for this because it will be greater than 4GBs,
>>
>>So?
>
> You don't get it do you?
Get what? Modern versions of tar can create archive files of
greater than 2 or 4 gigabytes.
linux% ls -l 5gigabyte.zip
-rw-r--r-- 1 jms jms 5751592946 May 3 19:37 5gigabyte.zip
linux% tar cf 5gb.tar 2005-03-01.zip
linux% ls -l 5gb.tar
-rw-r--r-- 1 jms jms 5751603200 Aug 9 22:30 5gb.tar
So why do you say 4GB wont work?
-Joe
------------------------------
Date: 9 Aug 2005 19:35:10 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: ignore new line for long string
Message-Id: <ddb0he$7c8$1@mamenchi.zrz.TU-Berlin.DE>
Noname <Noname@hot.com> wrote in comp.lang.perl.misc:
> Anno Siegel wrote:
>
> > Stephen Hildrey <steve@uptime.org.uk> wrote in comp.lang.perl.misc:
> > > ngoc wrote:
> > > > Hi
> > > > I have a very long string. Code will be ugly (not easy to
> > > > navigate for reading) if I write it in a line.
> > > > I want to write it in many lines, but treat as one line long
> > > > string. How can I do it ?
> > >
> > > code:
> > >
> > > use strict;
> > > use warnings;
> > >
> > > (my $long = <<EOLONG) =~ tr/\n/ /;
> > > This is a
> > > really really really
> > > long string
> > > EOLONG
> > >
> > > print $long, "\n";
> > >
> > > ===
> > >
> > > output:
> > >
> > > This is a really really really long string
> >
> > What if the string is supposed to contain newlines?
> >
> > my $long = 'This is a' .
> > ' really really really' .
> > ' long string';
> > print "$long\n";
> >
> > Anno
>
> Then OP is supposed to use his head, Stephen tought him where to fish
Not really. He showed a solution using a here-document, which has no
advantages over "" in the representation of long lines. Deleting the
line-feeds after the fact is a possibility, but as I pointed out, it
doesn't allow for the string to contain the occasional line feed, so
it has restrictions.
The standard solution is to concatenate the string from manageable
pieces.
Anno
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------------------------------
Date: 9 Aug 2005 20:09:46 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Naive Unix Socket client
Message-Id: <ddb2ia$7c8$4@mamenchi.zrz.TU-Berlin.DE>
Herb Martin <news@LearnQuick.com> wrote in comp.lang.perl.misc:
> "Anno Siegel" <anno4000@lublin.zrz.tu-berlin.de> wrote in message
> news:dd7gmi$sv9$1@mamenchi.zrz.TU-Berlin.DE...
> > For a simple way to create a socket try Net::EasyTCP.
>
>
> Net::EasyTCP doesn't seem to have anything to do with UNIX
> Sockets but is instead about INET Sockets.
>
> Do you use this with Unix sockets?
Sorry, I didn't notice you were specifically working with Unix domain
sockets.
Anno
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------------------------------
Date: Wed, 10 Aug 2005 12:32:28 +0530
From: vikrant <vikrantREMOVE@DELETEsaysnetsoft.com>
Subject: Problem in passing values to perl script using another perl script
Message-Id: <ddc8ss$map$1@domitilla.aioe.org>
hi
i have two perl scripts user.pl and user_database.pl
user.pl #script store in /home/bob directory
--------------------------------
#!/usr/bin/perl
print"Enter the user name";
$name = <STDIN>;
print "$name";
----------------------------------
user_database.pl # script store in /home/bob directory
----------------------------------
#!/usr/bin/perl
$user_name = "BOB";
system("perl /home/bob/user.pl");
--------------------------------
# output after running user_database.pl
Enter the user name
It asked me to enter user name. Now,i have to enter the value using my
keyboard but i do not want to do so.
i want that the value of "$user_name" pass to this automatically.
But,i am not able to do so.
Due to some reason i do not want to make use of command line arguments.
Actullay,I am new to perl so please let me know if am missing something.
With Regards
Vikrant
------------------------------
Date: Wed, 10 Aug 2005 09:33:33 +0200
From: Gunnar Hjalmarsson <noreply@gunnar.cc>
Subject: Re: Problem in passing values to perl script using another perl script
Message-Id: <3ltoujF145fc0U1@individual.net>
vikrant wrote:
> i have two perl scripts user.pl and user_database.pl
>
> user.pl #script store in /home/bob directory
> --------------------------------
> #!/usr/bin/perl
> print"Enter the user name";
> $name = <STDIN>;
> print "$name";
> ----------------------------------
>
>
> user_database.pl # script store in /home/bob directory
> ----------------------------------
> #!/usr/bin/perl
> $user_name = "BOB";
>
> system("perl /home/bob/user.pl");
>
> --------------------------------
> # output after running user_database.pl
>
> Enter the user name
>
> It asked me to enter user name. Now,i have to enter the value using my
> keyboard but i do not want to do so.
>
> i want that the value of "$user_name" pass to this automatically.
Then make use of the @ARGV variable and don't fork a new process, i.e.
use do() or require() instead of system().
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
------------------------------
Date: Wed, 10 Aug 2005 01:08:46 -0700
From: Joe Smith <joe@inwap.com>
Subject: Re: Problem in passing values to perl script using another perl script
Message-Id: <Kq-dnZ2dnZ1tIcXLnZ2dnYorZN-dnZ2dRVn-yZ2dnZ0@comcast.com>
vikrant wrote:
> #!/usr/bin/perl
> $user_name = "BOB";
>
> system("perl /home/bob/user.pl");
$user_name = 'BOB';
open my $pipe,'|-','perl /home/bob/user.pl'
or die "Could not open pipe: $!";
print $pipe $user_name,"\n";
close $pipe or warn "Problems on pipe close: $!";
This is assuming you really have a need for executing user.pl
as a separate process, as opposed to using
use '/home/bob/user.pl';
or
require '/home/bob/user.pl';
-Joe
------------------------------
Date: Wed, 10 Aug 2005 14:40:06 +0530
From: vikrant <vikrantREMOVE@DELETEsaysnetsoft.com>
Subject: Re: Problem in passing values to perl script using another perl script
Message-Id: <ddcgc4$336$1@domitilla.aioe.org>
Thanks for the information.
Vikrant
------------------------------
Date: Wed, 10 Aug 2005 08:05:09 +1000
From: Damian James <djames@thehub.com.au>
Subject: Re: Simple Question about Scalars
Message-Id: <slrndfia4h.3kv.djames@puli.home>
On Tue, 9 Aug 2005 18:14:32 +0100, David Young said:
> Quite new to Perl and I have a really simple question .... I have a scalar
> varible which could contain a string of a numberic value ....
> How can I tell if a scalar contains a string or a value?
>
Have a look over the perldata man page, in the section headed "scalar
values". This contains a general discussion of the issue, and suggests
a simple way to tell, and some more involved ways.
perldoc perldata
should show you this page, otherwise see the documentation for your
distribution.
--Damian
--
@:=grep!(m!$/|#!..$|),split//,<DATA>;@;=0..$#:;while($:=@;){$;=rand
$:--,@;[$;,$:]=@;[$:,$;]while$:;push@|,shift@;if$;[0]==@|;select$,,
$,,$,,1/80;print qq x\bxx((@;+@|)*$|++),@:[@|,@;],!@;&&$/} __END__
Just another Perl Hacker,### http://home.pacific.net.au/~djames.hub
------------------------------
Date: Wed, 10 Aug 2005 12:38:14 +0300
From: "Veli-Pekka Tätilä" <vtatila@mail.student.oulu.fi>
Subject: Re: Simple Question about Scalars
Message-Id: <ddchug$nm5$1@news.oulu.fi>
David Young wrote:
> Quite new to Perl and I have a really simple question
Nothing wrong with that <wink>. I'm a bit of a newbie myself and hope these
kind of simple questions are all right in here.
> How can I tell if a scalar contains a string or a value?
You mean string or a number. You could use regular expressions as suggested
by others.
One thing that no-one's yet mentioned, at least when I started writing this,
is the Scalar::Util module. I'm not sure about any other versions of Perl
but if you are running Active State Perl, you'll already have the module.
Here's how to determine if the first command-line argument is numeric:
use strict;
use warnings;
use English;
use Scalar::Util qw(looks_like_number);
local $OUTPUT_RECORD_SEPARATOR = "\n"; # Auto-print new-lines after prints.
my $scalar = $ARGV[0];
if(not defined $scalar)
{ # User didn't give any argument at all.
print "Please enter something after $PROGRAM_NAME.";
} # if
elsif(looks_like_number $scalar)
{ # We're dealing with a number here.
print "$scalar looks like a number to me.";
} # elsif
else
{ # Not a number => (NaN)
print "$scalar - that's no number.";
} # else
Points worthy of note:
1. The qw operator makes a list out of space delimited items this time a
single scalar. It follows the use statement and is not separated by a comma.
That idiom can be used to export function names directly in your name space.
If you didn't include the qw bit you would have to say:
Scalar::Util::looks_like_number()
which reminds me of Java in a negative way.
2. The English module let's one use readable variable names such as
$INPUT_RECORD_SEPARATOR. Here we've redefined the output record separator to
give a new-line after each print statement (output record or line if you
will). This ensures output behavior typical of DOS programs, that is two
line breaks before the prompt c:\> or whatever.
3. The looks_like_number function seems to work very well and might have a
faster version coded in C. SO I see no reason for having to match regular
expressions against numberness if any kind of number will do. IF you are
looking for particular kinds of numbers or numbers having certain properties
things will be different.
Hope this can be of help.
--
With kind regards Veli-Pekka Tätilä (vtatila@mail.student.oulu.fi)
Accessibility, game music, synthesizers and programming:
http://www.student.oulu.fi/~vtatila/
------------------------------
Date: Wed, 10 Aug 2005 17:13:20 +0000 (UTC)
From: Mark Shaw <mshaw@bangnetcom.com>
Subject: Re: Syntax highlighting in perl debugger
Message-Id: <dddcjg$c64$1@reader2.panix.com>
Mark Shaw <mshaw@bangnetcom.com> wrote:
> How does one turn OFF the syntax highlighting in the perl
> debugger?
> I'm running 5.8.0 under linux.
I find it hard to believe that nobody knows the answer to
this one....
--
Mark Shaw
========================================================================
"Labor to keep alive in your breast that little spark of mnshaw@
celestial fire called conscience." - George Washington gmail.com
------------------------------
Date: Wed, 10 Aug 2005 00:43:21 -0700
From: Joe Smith <joe@inwap.com>
Subject: Re: talking to a port, and server daemon: partly OT
Message-Id: <UM-dnV9szsW-LWTfRVn-pA@comcast.com>
Jeff Thies wrote:
> The way servebase works is that you send them name data pairs, either
> on the query string or using POST to their website script. SERVEBASE
> sends back XML on the *same* port.
Yes, that is how simple HTTP requests work.
1) Client creates bi-directional socket connecting to the remote
port where the server is listening.
2) Client sends headers and data to server, then closes the
client-to-server half of the socket.
3) Server sends headers and data back to client, then closes
the other half of the socket.
4) Transaction complete.
> Parsing the XML doesn't
> bother me, talking back and forth on the port does.
Oh you're talking about a non-simple HTTP transaction, where
multiple partial requests and responses are sent back and
forth in a half-duplex manner.
2a) Client sends headers with "Connection: keep-alive" and
a content-type indicating multiple parts will follow.
2b) Client sends the content-type and content-length of next part.
2c) Client sends data, the same number of bytes as described in
the Content-length header, does not close its end of the socket.
3a) Server sends headers and data back to client; headers include
a Content-length value.
3b) Server does not close its end of the socket.
4) Client parses the data it receives, decides if it needs to
send another part.
5) Repeat send-and-receive by looping back to step 2b.
Is that what you're trying to accomplish?
-Joe
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
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Subject: Digest Administrivia (Last modified: 6 Apr 01)
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------------------------------
End of Perl-Users Digest V10 Issue 8311
***************************************
