[9316] in Perl-Users-Digest
Perl-Users Digest, Issue: 2911 Volume: 8
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Jun 19 12:18:12 1998
Date: Fri, 19 Jun 98 09:00:31 -0700
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Fri, 19 Jun 1998 Volume: 8 Number: 2911
Today's topics:
Re: [Q] On WAKING a sleeping process... (Mark-Jason Dominus)
A script for Both CGI and command line? <quednauf@nortel.co.uk>
Re: A script for Both CGI and command line? dgris@rand.dimensional.com
Re: A script for Both CGI and command line? <Tony.Curtis+usenet@vcpc.univie.ac.at>
Appending one file to another <b-camp@students.uiuc.edu>
Re: Appending one file to another <psdspss@execpc.com>
Re: Array Combinations Question <jdporter@min.net>
Changing Computer Name/IP <nrd1mmc@nrd.ups.com>
Re: Code Efficiency <bowlin@sirius.com>
Re: first language <merlyn@stonehenge.com>
Re: first language <merlyn@stonehenge.com>
Re: first language (Mark-Jason Dominus)
Flames.... <psdspss@execpc.com>
Re: Flames.... <jdporter@min.net>
Re: Foreach Efficiency (Josh Kortbein)
Re: formline and predefined formats <markjones@mindless.com>
Re: formline and predefined formats <markjones@mindless.com>
Re: Get IP Address for Server Name <aqumsieh@matrox.com>
Re: Help combining two files. (steve)
help comparing strings jay_st_louis@my-dejanews.com
help with string comparisons jay_st_louis@my-dejanews.com
Re: javascript and perl <quednauf@nortel.co.uk>
Re: javascript and perl <bowlin@sirius.com>
Re: javascript and perl <dturley@ravine.binary.net>
Re: Making Life Easy - Templates, XSSI, Variables and s <bowlin@sirius.com>
Re: Pod::Text -- Unix only? (Stuart McDow)
Re: Problem using rsh within PERL <aqumsieh@matrox.com>
Re: Problem with references <jdf@pobox.com>
Re: Problem with references (Mark-Jason Dominus)
Re: Reference to arrays <jdf@pobox.com>
Re: Reference to arrays (Mark-Jason Dominus)
Re: Regex Help! (Dave Lorand)
Re: REVIEW: Perl CGI Programming - No Experience Requir <jdf@pobox.com>
Re: Sorting IP's - Help! <jdporter@min.net>
Re: Sorting IP's - Help! (Larry Rosler)
Re: subroutines <jdporter@min.net>
Re: subroutines <quednauf@nortel.co.uk>
Re: Subtracting Number of seconds from a date <mat.r@ukonline.co.uk>
Re: the ?PATTERN? match syntax <jdf@pobox.com>
Re: the ?PATTERN? match syntax <tchrist@mox.perl.com>
Digest Administrivia (Last modified: 8 Mar 97) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 19 Jun 1998 11:53:11 -0400
From: mjd@op.net (Mark-Jason Dominus)
Subject: Re: [Q] On WAKING a sleeping process...
Message-Id: <6me1h7$ivp$1@monet.op.net>
In article <Pine.GSO.3.96.980619004558.17544V-100000@user2.teleport.com>,
Tom Phoenix <rootbeer@teleport.com> wrote:
>Send it a signal; see the perlfunc and perlipc manpages. Hope this helps!
Well, it doesn't help me, and I'm supposed to know what is going on.
So perhaps you could elaborate on this a little. Does it work to send
a sleeping process the alarm clock signal? Is that portable? Are you
sure? What were you thinking of here?
I would have said to use a busy-loop like this:
# Name of file whose presence awakens Sleeping Beauty
use constant HEY_WAKE_UP => 'wake_up_you_slug';
$nap_start = time;
while (time < $nap_start + 3600) { # Nap for one hour
sleep 300; # Doze for five minutes
if (-e HEY_WAKE_UP) {
do_something_interesting();
unlink HEY_WAKE_UP;
# Possibly reset $nap_start now.
}
}
Then if you want Sleeping Beauty to wake up and do something
interesting here, you touch `wake_up_you_slug' in the appropriate
directory, and it wakes up within five minutes.
Of course, there are obvious disadvantages to this, but on the bright
side, it avoids signals, which is always a good thing.
Also it is a refutation of the `never use -e' dictum.
------------------------------
Date: Fri, 19 Jun 1998 15:21:16 +0100
From: "F.Quednau" <quednauf@nortel.co.uk>
Subject: A script for Both CGI and command line?
Message-Id: <358A73DB.9C2F20B7@nortel.co.uk>
Hello there,
I suspect there isn't an easy answer to this question, anyway:
If I run a script based on CGI.pm on the command line, I can enter the arguments
as name=value pairs in offline mode. Well, is there a way to write a script so
that it will load CGI.pm when called by the webserver, and produce a form, etc.
to get the needed values, but will also accept something like 'myscript.pl arg1
arg2 etc.' when called through command line?
Cheers,
--
____________________________________________________________
Frank Quednau
http://www.surrey.ac.uk/~me51fq
________________________________________________
------------------------------
Date: Fri, 19 Jun 1998 14:48:10 GMT
From: dgris@rand.dimensional.com
Subject: Re: A script for Both CGI and command line?
Message-Id: <6mdt3k$4ud$1@rand.dimensional.com>
[posted and mailed]
In article <358A73DB.9C2F20B7@nortel.co.uk>,
F.Quednau <quednauf@nortel.co.uk> wrote:
> Well, is there a way to write a script so that
>it will load CGI.pm when called by the webserver, and produce a form, etc.
>to get the needed values, but will also accept something like 'myscript.pl
>arg1 arg2 etc.' when called through command line?
>
I'd do this-
#!/usr/bin/perl -w
use strict;
do_common_initialization_stuff;
if(@ARGV){
do_stuff_for_command_line_mode;
}
else {
do_stuff_for_cgi_mode;
}
>Frank Quednau
Daniel
--
Daniel Grisinger dgris@perrin.dimensional.com
"No kings, no presidents, just a rough consensus and
running code."
Dave Clark
------------------------------
Date: 19 Jun 1998 16:59:39 +0200
From: Tony Curtis <Tony.Curtis+usenet@vcpc.univie.ac.at>
To: quednauf@nortel.co.uk
Subject: Re: A script for Both CGI and command line?
Message-Id: <7xra0lphd0.fsf@beavis.vcpc.univie.ac.at>
Re: A script for Both CGI and command line?, F
<quednauf@nortel.co.uk> said:
F> If I run a script based on CGI.pm on the command line, I
F> can enter the arguments as name=value pairs in offline
F> mode. Well, is there a way to write a script so that it
F> will load CGI.pm when called by the webserver, and
F> produce a form, etc. to get the needed values, but will
F> also accept something like 'myscript.pl arg1 arg2 etc.'
F> when called through command line?
CGI.pm already does this for you (but of course :-).
In the `offline mode' you can pass the args on the command
line, viz.
perl script.cgi name=tony iq=190
If you pass no command line arguments then it reads from
stdin.
hth
tony
--
Tony Curtis, Systems Manager, VCPC, | Tel +43 1 310 93 96 - 12; Fax - 13
Liechtensteinstrasse 22, A-1090 Wien, AT | http://www.vcpc.univie.ac.at/
"You see? You see? Your stupid minds! Stupid! Stupid!" ~ Eros, Plan9 fOS.
------------------------------
Date: Fri, 19 Jun 1998 09:19:13 -0500
From: Bryan Camp <b-camp@students.uiuc.edu>
Subject: Appending one file to another
Message-Id: <Pine.SOL.3.96.980619090344.8407A-100000@ux10.cso.uiuc.edu>
Hello,
I've been struggling on a very simple matter.
What I'm trying to do is append one file on to
the end of another file.
For example, 'output_file' is a file that
I would like to append onto an already existing
file, which was earlier named by the user.
open(HANDLE, ">> $user_named") || die;
print HANDLE output_file;
On the second line, I have tried placing
single, double, and no quotes around output_file,
but all this does is write the word "output_file"
to the user-named file insted of the output_file
itself. Could someone help me fix this problem?
Thanks.
Bryan
------------------------------
Date: Fri, 19 Jun 1998 09:45:50 -0500
From: Deva Seetharam <psdspss@execpc.com>
Subject: Re: Appending one file to another
Message-Id: <358A799E.36E8423E@execpc.com>
Bryan Camp wrote:
> Hello,
>
> I've been struggling on a very simple matter.
> What I'm trying to do is append one file on to
> the end of another file.
> For example, 'output_file' is a file that
> I would like to append onto an already existing
> file, which was earlier named by the user.
>
> open(HANDLE, ">> $user_named") || die;
> print HANDLE output_file;
>
> On the second line, I have tried placing
> single, double, and no quotes around output_file,
> but all this does is write the word "output_file"
> to the user-named file insted of the output_file
> itself. Could someone help me fix this problem?
> Thanks.
>
> Bryan
output_file is just a string.What u need is actually the set of records
in the output file.
So u need to open the output_file and read the records. Then these
records can be appended. For example :
#/usr/bin/perl
open(TAIL, "<./data2") or die "Could not open the file : $!";
open(HEAD, ">>./data1") or die "Could not open the file : $!";
print HEAD <TAIL>;
<TAIL> returns all the records pointed by TAIL file handle.
Hope that helps.
Please read thru Learning Perl by Randal Schwartz for a better
understanding
of the language.
Deva
------------------------------
Date: Fri, 19 Jun 1998 15:05:34 GMT
From: John Porter <jdporter@min.net>
Subject: Re: Array Combinations Question
Message-Id: <358A7FF4.5B2@min.net>
Randal Schwartz wrote:
>
> F> John Porter wrote:
> >> for ( rec( \@array ) ) {
> >> print "$_\n";
> >> }
> >>
> >> sub rec {
> >> my( $ar, @stack ) = @_;
> >> return "@stack" unless @$ar;
> >> my( $head, @a ) = @$ar;
> >> map { rec( \@a, @stack, $_ ) } @$head;
> >> }
> If that was *my* code, I'd have put the comment "NO USER SERVICABLE
> PARTS INSIDE" above it. :-)
Well, actually there is at least one, as I mentioned in the original
post.
--
John Porter
------------------------------
Date: Fri, 19 Jun 1998 10:22:01 -0400
From: "Murtuza Chhil" <nrd1mmc@nrd.ups.com>
Subject: Changing Computer Name/IP
Message-Id: <6mds6d$im41@biko.telecom.ups.com>
Hi,
Is it possible to change the IP address and computer name on a NT machine
using perl....
Any help is appreciated.
Thanx
Chhil
------------------------------
Date: Fri, 19 Jun 1998 07:13:04 -0700
From: Jim Bowlin <bowlin@sirius.com>
To: Ray Smith <ismithr@info.curtin.edu.au>
Subject: Re: Code Efficiency
Message-Id: <358A71F0.29C19BB4@sirius.com>
Ray Smith wrote:
>
> Hi all,
>
> I have written a perl program that builds an HTML table of currently
> booked records. The code first serach for all valid entires, based on a
> room ID and a date code. I'm using DB_File for this so its a little
> slow (about 1.5 secs to go through 3500 entries), but I'll be installing
> oracle shortly so should be able to over come this. The problem I'm
> having is that once the required entries have been retreived in need to
> produce an HTML table of the data. This table is taking 8 secs to be
> printed out. Can anyone give me some tips on speeding this up?? I'm
> running perl 5.004 in IRIX 6.3.
>
> Thanks for you time and any information, Ray.
I have some suggestions. Some of these will make it easier for you
(and others including c.l.p.m) to understand your code which will
eventually lead to your desired goal of faster run times.
1) Use my instead of local.
2) Use foreach() instead of for(;;) when you can.
3) Make your comments more distinguishable from your code.
4) don't bury your main code under an if (open(A, a))
instead put error code near the open statement.
5) Use a hash lookup instead of a long if ... elsif chain.
6) Don't keep splitting elements of @entries inside a loop,
instead split this stuff once and store it in a structure.
7) Read the section on efficency in the Camel Book.
HTH -- Jim Bowlin
------------------------------
Date: Fri, 19 Jun 1998 14:39:09 GMT
From: Randal Schwartz <merlyn@stonehenge.com>
Subject: Re: first language
Message-Id: <8cbtrpbgn2.fsf@gadget.cscaper.com>
>>>>> "Dan" == Dan Nguyen <nguyend7@egr.msu.edu> writes:
Dan> The person needs to be a "natural" programmer. Generally I feel that
Dan> most people have hard time not with the language but with the process
Dan> of programming. A person could learn Perl as a first language very
Dan> easily and have no problems, while others could become stuck on the
Dan> syntax of the language.
I'll second this. I see far too many people *attempting* programming
that would probably have a better time being firefighters or line
chefs or congressmen or something. Sure, maybe nearly anyone with
enough effort can hack out a VB script to automate a repeated task,
but programming *well* seems to require a twisted aptitude only some
small percentage of the population seems to have. I think I was lucky
to be born with it, given the time at which I was born. :-) No
ordinary amount of education can seem to teach people how to "think"
like a progammer. ("You have these seven transformations possible and
this problem requires converting Q to W... go!")
I suppose it would be too much to ask that if you're not a natural
programmer, either stay out of the business, or flag your work
properly so that we cleanup people know what to throw out first. :-)
On the other hand, *I* can't draw worth beans. It's a struggle for
me. Huge. No amount of education is gonna fix that. So, it's a good
thing that there are artists for hire out there. I think in the end,
it all balances out. I can't cook either. But I know how to operate
a VISA card at a restaurant. :-)
print "Just another Perl hacker," # but not what the media calls "hacker!" :-)
## legal fund: $20,990.69 collected, $186,159.85 spent; just 74 more days
## before I go to *prison* for 90 days; email fund@stonehenge.com for details
--
Name: Randal L. Schwartz / Stonehenge Consulting Services (503)777-0095
Keywords: Perl training, UNIX[tm] consulting, video production, skiing, flying
Email: <merlyn@stonehenge.com> Snail: (Call) PGP-Key: (finger merlyn@teleport.com)
Web: <A HREF="http://www.stonehenge.com/merlyn/">My Home Page!</A>
Quote: "I'm telling you, if I could have five lines in my .sig, I would!" -- me
------------------------------
Date: Fri, 19 Jun 1998 14:41:49 GMT
From: Randal Schwartz <merlyn@stonehenge.com>
Subject: Re: first language
Message-Id: <8c7m2dbgim.fsf@gadget.cscaper.com>
>>>>> "Dan" == Dan Nguyen <nguyend7@egr.msu.edu> writes:
Dan> Pascal is a good language (though it is begining to be taught in fewer
Dan> and fewer high schools.) to learn. One of the things that helps
Dan> begining programmers is the strictness of the language. Generally
Dan> there is either one way or a few ways of doing things. That one way
Dan> usually is the best for most situation. Though it may not always
Dan> produce the most effient code.
I tell people frequently:
To master structured programming, learn Pascal *first*.
To master object-oriented programing, learn Smalltalk *first*.
There's no excuse for not knowing Pascal and Smalltalk given the free
implementations out there.
print "Just another Perl hacker," # but not what the media calls "hacker!" :-)
## legal fund: $20,990.69 collected, $186,159.85 spent; just 74 more days
## before I go to *prison* for 90 days; email fund@stonehenge.com for details
--
Name: Randal L. Schwartz / Stonehenge Consulting Services (503)777-0095
Keywords: Perl training, UNIX[tm] consulting, video production, skiing, flying
Email: <merlyn@stonehenge.com> Snail: (Call) PGP-Key: (finger merlyn@teleport.com)
Web: <A HREF="http://www.stonehenge.com/merlyn/">My Home Page!</A>
Quote: "I'm telling you, if I could have five lines in my .sig, I would!" -- me
------------------------------
Date: 19 Jun 1998 11:44:55 -0400
From: mjd@op.net (Mark-Jason Dominus)
Subject: Re: first language
Message-Id: <6me11n$itv$1@monet.op.net>
In article <MPG.ff322ab6ba60ca098969c@nntp.hpl.hp.com>,
Larry Rosler <lr@hpl.hp.com> wrote:
>As one of the first who tried to teach C many years ago, I can vouch that
>it is a poor choice for beginners, for one spcific reason that is seldom
>discussed: the difficulty of doing simple text input with data
>conversion.
>
>Once one gets past single-character input (getchar or getc) or perhaps
>line-at-a-time-and-parse-it-yourself input (gets or fgets, atoi, atof,
>...), one encounters the horrible scanf function, which demands an
>understanding of pointers and internal representations. Fuggedaboudit!
I had to teach an introductory programming course in C to people with
no programming experience, and the first thing I realized was the
problem you describe.
So I pondered my two choices: (1) Avoid sprintf, perhaps by giving them a
library of special-purpose input routines, or (2) Cover pointers very
early on.
I decided that (1) was essentially a waste of time, because the skills
and techniques they learned for dealing with my special-purpose input
functions would be useless.
But more important, I asked myself where the problem was really coming
from. I want to teach scanf, but to do that, I have to teach
pointers. Why does scanf need pointers?
`scanf' needs pointers because without them it cannot modify variables
in the calling subroutine. Why not?
`scanf' cannot modify variables in the calling subroutine without
pointers because the variables are lexically scoped so that they can
be hidden from other subroutines.
That decided me. Data hiding and encapsulation issues must be at the
heart of any programming course. By avoiding pointers, I would be
avoiding these elementary issues.
It turned out that pointers were very important and very essential.
They presented themselves in the earliest parts of the material not
out of perversity, but because they were central to the topic.
So I went with choice 2, and I discussed functions and private
variables in the second lecture. Then, by the fourth lecture, with
the idea of private variables already established, I discussed scanf
and pointers. I did not discuss arrays or pointer arithmetic until
much later.
This all worked very well. It is a very little pill to swallow.
Everyone understood. Later on, when we discussed arrays, the pointer
arithmetic part was a smaller pill because everyone was already
familiar with pointers.
It was a huge success, and it left me convinced that the problems with
teaching people pointers are on the delivering end, not the receiving
end. I think that people teach pointers the wrong way, and usually
the instructors do not understand pointers themselves.
Summary:
Pointers are an essential part of the solution to the data hiding
problem, which is an essential issue. Therefore, they cannot be
avoided, and in fact should be addressed as soon as possible. The
idea of a pointer should be separated from issues of pointer
arithmetic, which is not necessary until later.
Note crossposting.
------------------------------
Date: Fri, 19 Jun 1998 10:09:58 -0500
From: Deva Seetharam <psdspss@execpc.com>
Subject: Flames....
Message-Id: <358A7F45.3FA55ADA@execpc.com>
Why do people get mad, when anybody posts a basic/repeat question ?
Person who is posting basic/repeat should be either :
Ignorant (of the resources/references) or
Incompetent (to seek resources/references) or
Lazy (to look at resources/references) or
Neurotic (Posts the question with the intention to irritate)
Probability for 4th option is pretty less, given the fact that, there
are so many interesting and easier ways to satisfy such intentions.
If somebody thinks the question is stupid/irrelevant/repeated, why
can't he/she disregard the question ?
Blasting does not serve any purpose, other than discourage the newbie.
Why to do that ? Even learning to program, is a metamorphosis.
I think the initial phases are inevitable.
(Everyone, atleast once, had a tough time to go
1,2,3,4....)
Deva
------------------------------
Date: Fri, 19 Jun 1998 15:22:52 GMT
From: John Porter <jdporter@min.net>
Subject: Re: Flames....
Message-Id: <358A8403.2255@min.net>
Deva Seetharam wrote:
>
> Why do people get mad, when anybody posts a basic/repeat question ?
>...
(Ah, the Meta-FAQ :-)
This issue has been beaten do death already in this (and every other)
newsgroup. You would know this, and more to the point, you would
know in great detail how many of clpm's denizens feel about this
issue, if you had spent a little time reading the archives of
this newsgroup, which are available at DejaNews and even AltaVista
(although not as far back).
--
John Porter
------------------------------
Date: 19 Jun 1998 14:16:46 GMT
From: kortbein@iastate.edu (Josh Kortbein)
Subject: Re: Foreach Efficiency
Message-Id: <6mdrse$1tl$1@news.iastate.edu>
Ronald J Kimball (rjk@coos.dartmouth.edu) wrote:
: Peter A Fein <p-fein@uchicago.edu> wrote:
: > > > Well, because I have finals in a few days and I need to get this
: > > > working yesterday. Although I'd like to mess around & benchmark parts
: > > > of my code at some point, that point is not now.
: > >
: > > In that case, why are you bothering with usenet at all?
: > > [...]
: >
: > Posting takes a few seconds tops. Compared to d/l'd, installing,
: > reading the docs, altering my code, running it, restoring my code &
: > then debugging the bugs I just introduced by doing this. ;)
: > Whatever. Look, it works, thanks for the pointer to Benchmark.
: In other words, you're foisting off all the work onto us. Thank you so
: much.
It's only work foisted if you bite the hook. If your time was that
important, would you even be replying to questions at all? Or discussing
your replies to them?
Josh
--
____________________________________________________________________
"In Zen they say: If something is boring after 2 minutes, try it for
4. If still boring, try it for 8, 16, 32, and so on. Eventually one
discovers that it's not boring at all but very interesting."
- John Cage
------------------------------
Date: Fri, 19 Jun 1998 09:07:03 -0500
From: Mark Evan Jones <markjones@mindless.com>
Subject: Re: formline and predefined formats
Message-Id: <358A7087.C17D48A7@mindless.com>
Mark Evan Jones wrote:
Heh. My last version worked, except for the fact that formline takes
only 2 arguments, a picture and a LIST...so while
formline( SIMPLE, 1, 2, 3);
doesn't work,
formline( SIMPLE (1,2,3) );
does. Thanks for putting up with a silly question...
> Is it possible to use formline and specify only a predefined format
> instead of duplicating the picture every time? ie, instead of
>
> formline ('@<<< @||| @>>>', 1, 2, 3);
> print "$^A\n";
>
> or
>
> formline <<'END',1,2,3;
> @<<< @||| @>>>
> END
> print "$^A\n";
>
> can I do something like:
>
> formline (SIMPLE, 1, 2, 3)
> $temp = $^A;
>
> format SIMPLE =
> @<<< @||| @>>>
> $one, $two, $three
> .
------------------------------
Date: Fri, 19 Jun 1998 09:09:35 -0500
From: Mark Evan Jones <markjones@mindless.com>
Subject: Re: formline and predefined formats
Message-Id: <358A711F.59E9F015@mindless.com>
Wait..I take that back...I'm still screwed up...disreguard my previous
reply to my own note...
It was suggested to me to put the format into a variable...how do I
accomplish this?
$var = format SIMPLE =
blah blah blah
.
doesn't seem to work...
I guess I need more sleep...
------------------------------
Date: Fri, 19 Jun 1998 09:27:58 -0400
From: Ala Qumsieh <aqumsieh@matrox.com>
Subject: Re: Get IP Address for Server Name
Message-Id: <358A675E.E35C9116@matrox.com>
Matthew Feinberg wrote:
>
> Hi,
>
> Does anyone have a script that will get the IP address for a servername
> given.
>
> i.e.
>
> ./findip server.somedomain.com
>
> returns ip address i.e. 209.191.4.200
>
> Thanks
nslookup does it for you.
--
Ala Qumsieh | No .. not just another
ASIC Design Engineer | Perl Hacker!!!!!
Matrox Graphics Inc. |
Montreal, Quebec | (Not yet!)
------------------------------
Date: Fri, 19 Jun 98 15:50:54 GMT
From: matkoski@ELIMINATE.THIS.appliedtheory.com (steve)
Subject: Re: Help combining two files.
Message-Id: <6me18n$94$1@news.appliedtheory.com>
In article <6mcl87$kj0@newsops.execpc.com>, Deva Seetharam <psdspss@execpc.com> wrote:
>I was just wondering, what if you could prepare a list of forbidden newsgroups,
>and prevent the user(s) from accessing those newsgroups.
>
>1. Read the files.
>2. Prepare a list of forbidden newsgroups by selecting the ones
> that are preceded by '!'.
>3. Check whether the requested newsgroup is in the forbidden list.
> If so, prevent access.
>
>This method does not require any sorting to be done.
>
I never gave you the whole picture of what I was doing and this is only a part
of it. I am writing a web interface that allows an admin to log into a web
site and choose the groups he/she would allow or disallow a group of people to
read. So I have to combine the choices this admin chooses from the web
interface with a file that contains their current newsgroup listing.
------------------------------
Date: Fri, 19 Jun 1998 15:36:11 GMT
From: jay_st_louis@my-dejanews.com
Subject: help comparing strings
Message-Id: <6me0hb$cdk$1@nnrp1.dejanews.com>
I was wondering if it was possible to compare a specific length of a string
using Perl, like strncmp in C. What I mean is that I only want to compare
the first 5 characters of a string to the first 5 characters of another
string. Can it be done?
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
http://www.dejanews.com/ Now offering spam-free web-based newsreading
------------------------------
Date: Fri, 19 Jun 1998 15:47:36 GMT
From: jay_st_louis@my-dejanews.com
Subject: help with string comparisons
Message-Id: <6me16o$dgr$1@nnrp1.dejanews.com>
I was wondering if there is a way to compare a specific number of characters
in a string in Perl, like using strncmp in C. for example, if I wanted to
compare just the first five characters of 2 strings that were 20 characters
long. can this be done?
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
http://www.dejanews.com/ Now offering spam-free web-based newsreading
------------------------------
Date: Fri, 19 Jun 1998 15:52:46 +0100
From: "F.Quednau" <quednauf@nortel.co.uk>
Subject: Re: javascript and perl
Message-Id: <358A7B3E.E3FD7DE8@nortel.co.uk>
Inge Soetens wrote:
>
> Hi,
>
> Can anyone tell me....
> Is it possible to call a perl procedure from a javascript function ?
>
> Thanks
You could probably call a script which takes as an argument as to which
procedure to execute.
JSCRIPT>window.href.location="http://sillydomainname.org/cgi/perldang.pl?procedure=dingalinglong"
PERL>
#usa/wastebin/perl
.
.
.
$proc eq "dingalinglong" ? &dingalinglong : print "I am bored. Gimmewattodo";
--
____________________________________________________________
Frank Quednau
http://www.surrey.ac.uk/~me51fq
________________________________________________
------------------------------
Date: Fri, 19 Jun 1998 07:57:20 -0700
From: Jim Bowlin <bowlin@sirius.com>
To: Inge Soetens <soetensi@se.bel.alcatel.be>
Subject: Re: javascript and perl
Message-Id: <358A7C50.210A9777@sirius.com>
Inge Soetens wrote:
>
> Hi,
>
> Can anyone tell me....
> Is it possible to call a perl procedure from a javascript function ?
>
> Thanks
No. -- Jim Bowlin
------------------------------
Date: 19 Jun 1998 15:45:05 GMT
From: David Turley <dturley@ravine.binary.net>
Subject: Re: javascript and perl
Message-Id: <6me121$iab$1@oksennus.binary.net>
In comp.lang.perl.misc Jim Bowlin <bowlin@sirius.com> wrote:
> Inge Soetens wrote:
> >
> > Hi,
> >
> > Can anyone tell me....
> > Is it possible to call a perl procedure from a javascript function ?
> >
> > Thanks
> No. -- Jim Bowlin
Why not?
In the function:
document.location="../cgi-bin/myscript.pl";
I do it all the time.--
_____________________________________________________________________
David Turley
dturley@pobox.com
http://www.pobox.com/~dturley
"You don't want to be the only person sitting on a crocodile's back."
-- heard on a PBS nature show
______________________________________________________________________
------------------------------
Date: Fri, 19 Jun 1998 07:17:39 -0700
From: Jim Bowlin <bowlin@sirius.com>
To: Andy Wardley <abw@cre.canon.co.uk>
Subject: Re: Making Life Easy - Templates, XSSI, Variables and such
Message-Id: <358A7303.D08BE668@sirius.com>
Andy,
I downloaded Text::MetaText. It looks fabulous! I'll let you
know if I have any luck running it under NT. From the docs,
it seems to be just what I've been looking for.
Thanks, -- Jim Bowlin
------------------------------
Date: 19 Jun 1998 15:51:31 GMT
From: smcdow@arlut.utexas.edu (Stuart McDow)
Subject: Re: Pod::Text -- Unix only?
Message-Id: <6me1e3$ljm$1@ns1.arlut.utexas.edu>
pudge@pobox.com (Chris Nandor) writes:
>
> And if I wanted Pod::Text to determine screen width on my Mac, I
> would patch it myself using the $^O special variable,
And this is what it's all about. If you have a tool that doesn't do
what you want it to do, you hack it up so that it does. Whining to the
tool's writers demonstrates a very POBish mentality.
--
Stuart McDow Applied Research Laboratories
smcdow@arlut.utexas.edu The University of Texas at Austin
"Look for beauty in roughness, unpolishedness"
PS. After you've hacked it, be sure to send your changes to the tool's
maintainer.
------------------------------
Date: Fri, 19 Jun 1998 09:26:21 -0400
From: Ala Qumsieh <aqumsieh@matrox.com>
Subject: Re: Problem using rsh within PERL
Message-Id: <358A66FD.8CB2C855@matrox.com>
Hamish_Eassie wrote:
>
> Hi,
>
> I am writing a queueing system using PERL (Version 5) to run on solaris
> machines (SunOS 5.5.1) and am having a problem when using 'rsh' to batch
>
> off jobs in the background. I always batch off a csh script, but the
> problem is that if this shell script executes another shell script then
> the PERL script waits for all commands to complete, whereas if the csh
> script executes a compiled binary then the job is executed in the
> background as desired.
Try forking a child process and exec()ing your rsh command from within
the child process.
>
> Thanks,
>
> Hamish Eassie.
>
--
Ala Qumsieh | No .. not just another
ASIC Design Engineer | Perl Hacker!!!!!
Matrox Graphics Inc. |
Montreal, Quebec | (Not yet!)
------------------------------
Date: 19 Jun 1998 10:24:40 -0500
From: Jonathan Feinberg <jdf@pobox.com>
To: mjd@op.net (Mark-Jason Dominus)
Subject: Re: Problem with references
Message-Id: <vhpx5s93.fsf@mailhost.panix.com>
mjd@op.net (Mark-Jason Dominus) writes:
> In article <3589dda0.0@oit.umass.edu>, Nathan Weston
> <nathanw@post1.com> wrote:
>> Basically, I have a reference to an associative array, every
>> element of which contains a reference to another associative array.
>
> We like to say `hash' instead of `associative array', because that
> saves ten million syllables a year.
This got me thinking, and I decided to do a back-of-the-envelop check,
at least to see if your order of magnitude was correct.
By my thoroughly unscientific survey of DejaNews, I have determined
that there are a rough average of 16 messages a day that mention
"hash" or "associative array." Each message has an average of 4
mentions of the structure in question, for an average of 64 hashes a
day. Each use of "hash" represents a savings of 6 syllables over its
wordier cousin, for an average of 384 syllables saved per diem. Over
the course of a year, that's a mere 140,160 syllables saved.
Of course, everything's thrown way off by such posts as
http://x6.dejanews.com/getdoc.xp?AN=359588054
HTH.
--
Jonathan Feinberg jdf@pobox.com Sunny Brooklyn, NY
http://pobox.com/~jdf/
------------------------------
Date: 19 Jun 1998 10:53:18 -0400
From: mjd@op.net (Mark-Jason Dominus)
Subject: Re: Problem with references
Message-Id: <6mdu0u$iin$1@monet.op.net>
In article <vhpx5s93.fsf@mailhost.panix.com>,
Jonathan Feinberg <jdf@pobox.com> wrote:
>This got me thinking, and I decided to do a back-of-the-envelop check,
>at least to see if your order of magnitude was correct.
I imagined a thousand people each saying `hash' five or ten times a
day.
I also thought it was an undercount.
>By my thoroughly unscientific survey of DejaNews,
I think that's the wrong way to look for it, because (a) the big
savings is in speech, not in writing, and (b) you speak a lot more
than you write.
------------------------------
Date: 19 Jun 1998 10:42:40 -0500
From: Jonathan Feinberg <jdf@pobox.com>
To: "Thomas St. Pierre" <thomas@ikos.com>
Subject: Re: Reference to arrays
Message-Id: <ogvp5rf3.fsf@mailhost.panix.com>
"Thomas St. Pierre" <thomas@ikos.com> writes:
> 1) Why isn't it possible (or is it?) to create a symbolic reference
> to a single element of an array eg:
Why not take a real reference?
#!//c/perl/bin/perl -w
my @a = qw( abc def ghi jkl );
my $r = \$a[2];
print "$$r\n";
Please see perlref.
> let's say bit 0,1,4 and 5,7 go into file "input" 1,2,3,6,7 into file
> "output" (note that 1 and 7 are in both files)
Perhaps
chomp;
my @values = split '';
my @file_one_values = @values[0,1,4,5,7];
my @file_two_values = @values[1,2,3,6,7];
print FILE_ONE "@file_one_values\n";
print FILE_TWO "@file_two_values\n";
See perldata for array slices.
--
Jonathan Feinberg jdf@pobox.com Sunny Brooklyn, NY
http://pobox.com/~jdf/
------------------------------
Date: 19 Jun 1998 11:14:33 -0400
From: mjd@op.net (Mark-Jason Dominus)
Subject: Re: Reference to arrays
Message-Id: <6mdv8p$inh$1@monet.op.net>
In article <358A1F6F.85BA9E50@ikos.com>,
>1) Why isn't it possible (or is it?) to create a symbolic reference
>to a single element of an array eg:
>$test="egon[0]";
>$egon[0]="Guten Morgen";
>print $$test ,"\n";
Maybe you would like to do this:
$val = eval '$' . $test;
print $val, "\n";
>printing the $$test resolves in an empty string.
That is because there is no variable whose name is `egon[0]'.
I expect that the answer to `why' is `because it is not useful'.
>@line=split //,$_;
>line: [0|1|1|1|0|0|0|1]
>
>let's say bit 0,1,4 and 5,7 go into file "input" 1,2,3,6,7 into
>file "output" (note that 1 and 7 are in both files)
>
>My take was to generate a list of references for the input and the
> output file where every element of the list points to one element of
> the input array.
A Perl array contains slots that each contain one `SV' (scalar value)
structure. When you ask for $r = \$q[0], you get a reference to the
SV. If you then do $q[0] = 7, the SV in the array is replaced with a
new SV. $r still refers to the old SV, not to the new one. What you
want is for $r to point to a slot in the array, not to the SV.
What you want is pointers. In my opinion, pointers in Perl would be
terrible. A pointer to a variable that was later garbage-collected
would become invalid, and would make Perl dump core. A pointer to an
array that was relocated (or shortened) would be similarly invalid. A
pointer to $a[3] would turn into a point to $a[4] if you did `shift
@a', which is probably not what you want. People would want to do
pointer arithmetic. It would be all the hassles of C for none of the
benefit.
Anyway, in your problem the references are unnecessary.
@OUT1POS = (0,1,4,5,7);
@OUT2POS = (1,2,3,6,7);
while (<>) {
chomp;
my @line = split //, $_; ??;
my $OUT1 = join '', @line[@OUT1POS];
my $OUT2 = join '', @line[@OUT2POS];
# Do something with $OUT1 and $OUT2
}
Also, I think it's foolish to name an output file `input'. You should
give it some descriptive name that says what is in it. `input' is not
a descriptive name because any file can be the input to some program
and the output of some other program.
------------------------------
Date: Fri, 19 Jun 1998 15:03:58 GMT
From: davel@spc.uchicago.edu (Dave Lorand)
Subject: Re: Regex Help!
Message-Id: <davel-1906981003580001@honeybee.spc.uchicago.edu>
In article <6lrt6u$5q1$1@nnrp1.dejanews.com>, clay@crawlspace.com wrote:
> Hello --
>
> I could use some help with a regex that's kicking my inexperienced butt ...
> Here's some sample input:
>
> Database: mysql
> +--------+
> | Tables |
> +--------+
> | db |
> | func |
> | host |
> | user |
> +--------+
>
> Database: dngr
> +-------------+
> | Tables |
> +-------------+
> | dngr_comics |
> | dngr_images |
> | dngr_links |
> | dngr_rev |
> | poll |
> +-------------+
>
> Database: hotdogs
> +---------------------+
> | Tables |
> +---------------------+
> | hotdogs_with_cheese |
> | mustard_dogs |
> | relish_dogs |
> +---------------------+
>
>
> I've got an array containing all these lines (fed in from a mysqlshow
> command), and I need to get rid if all pipe characters, blank spaces, plus
> and dash symbols and the word "Tables" ... so that I'm left with only the
> table names.
>
> Also, I don't want the "Database: <name>" line either. The amount of white
> space varies depending on the output, as shown in the examples ..
>
> Can anyone lend a hand on this?
Clay,
Here's an option I haven't seen mentioned yet: use Perl's grep function.
Say you've got all these lines in @tables, and you've chop'ed or chomp'ed them.
Try this:
@tables = grep { s/^\|\s+(\w+)\s+\|$/$1/ and not /^Tables$/ } @tables;
(Sorry about the leaning-toothpicks syndrome.) Basically, grep iterates
over a list of values and returns a list of the ones for which the
expression in the block was true. The s/// removes the | and whitespace
around the name, and it will be false for the blank lines and the +---+
lines. The second one should be obvious - it excludes the "Tables" lines.
Regards,
Dave
____________________________________________________________
| Dave Lorand | davel@spc.uchicago.edu |
| Programmer/Analyst | 773-702-3792 |
| Social Science Research Computing | 773-702-0793 (dept.) |
| University of Chicago | 773-702-2101 (fax) |
+-----------------------------------+------------------------+
------------------------------
Date: 19 Jun 1998 10:45:21 -0500
From: Jonathan Feinberg <jdf@pobox.com>
To: c.c.eiftj@54.usenet.us.com (Rahul Dhesi)
Subject: Re: REVIEW: Perl CGI Programming - No Experience Required
Message-Id: <lnqt5ram.fsf@mailhost.panix.com>
c.c.eiftj@54.usenet.us.com (Rahul Dhesi) writes:
> Name-calling, obscure references to perl internals, and silly analogies.
> Are these what the original author of the 'Perl CGI Programming' should
> have used to explain perl arrays and lists?
You are being deliberately obtuse and inflammatory. We call it
"trolling." *plonk*
--
Jonathan Feinberg jdf@pobox.com Sunny Brooklyn, NY
http://pobox.com/~jdf/
------------------------------
Date: Fri, 19 Jun 1998 15:15:35 GMT
From: John Porter <jdporter@min.net>
Subject: Re: Sorting IP's - Help!
Message-Id: <358A824E.80B@min.net>
Rahul Dhesi wrote:
>
> sub cmp {
> @f1 = split(' ', $a);
> @f2 = split(' ', $b);
> ($a1, $a2, $a3, $a4) = split(/\./, $f1[2]);
> ($b1, $b2, $b3, $b4) = split(/\./, $f2[2]);
> ($a1 != $b1) && return $a1 - $b1;
> ($a2 != $b2) && return $a2 - $b2;
> ($a3 != $b3) && return $a3 - $b3;
> return $a4 - $b4;
> }
The end of that sub is more idiomatically written as:
$a1 <=> $b1
||
$a2 <=> $b2
||
$a3 <=> $b3
||
$a4 <=> $b4
}
--
John Porter
------------------------------
Date: Fri, 19 Jun 1998 08:36:58 -0700
From: lr@hpl.hp.com (Larry Rosler)
Subject: Re: Sorting IP's - Help!
Message-Id: <MPG.ff4257699f2382c9896d2@nntp.hpl.hp.com>
In article <6mcfu1$qg$1@samba.rahul.net>, Rahul Dhesi
<c.c.eiftj@41.usenet.us.com> says...
> In <3589744E.794B@boeing.com> David Pitts <david.pitts@boeing.com>
> writes:
>
> >What I am trying to do is sort this list by ip (there are thousands of
> >entries).
>
> The code below will sort lines in an array @lines if the third field is
> the IP address. To select a different field see $f1[2] and $f2[2]
> below.
>
> -- cut here --
> @lines = sort cmp @lines;
>
> print @lines;
>
> sub cmp {
> @f1 = split(' ', $a);
> @f2 = split(' ', $b);
> ($a1, $a2, $a3, $a4) = split(/\./, $f1[2]);
> ($b1, $b2, $b3, $b4) = split(/\./, $f2[2]);
> ($a1 != $b1) && return $a1 - $b1;
> ($a2 != $b2) && return $a2 - $b2;
> ($a3 != $b3) && return $a3 - $b3;
> return $a4 - $b4;
> }
> -- cut here --
> --
> Rahul Dhesi <dhesi@spams.r.us.com>
>
#!/usr/local/bin/perl -w
use Benchmark;
for ($i = 0; $i < 2000; ++$i) {
my @rand = ();
foreach ( 0 .. 3 ) { push @rand, int rand 256 }
push @lines, 'x y ' . join('.', @rand) . " z\n";
}
timethese (2, {
rahul => sub {
@out = sort {
@f1 = split(' ', $a);
@f2 = split(' ', $b);
($a1, $a2, $a3, $a4) = split(/\./, $f1[2]);
($b1, $b2, $b3, $b4) = split(/\./, $f2[2]);
($a1 != $b1) && return $a1 - $b1;
($a2 != $b2) && return $a2 - $b2;
($a3 != $b3) && return $a3 - $b3;
return $a4 - $b4;
} @lines
},
schwartz => sub {
@out = map $_->[0],
sort { $a->[1] <=> $b->[1] }
map { [ $_, sprintf '%.3d%.3d%.3d%.3d', split /\./, (split)[2] ] }
@lines
},
} );
Benchmark: timing 2 iterations of rahul, schwartz...
rahul: 26 secs (11.04 usr 0.06 sys = 11.10 cpu)
(warning: too few iterations for a reliable count)
schwartz: 4 secs ( 1.73 usr 0.02 sys = 1.75 cpu)
(warning: too few iterations for a reliable count)
--
Larry Rosler
Hewlett-Packard Laboratories
http://www.hpl.hp.com/personal/Larry_Rosler/
lr@hpl.hp.com
------------------------------
Date: Fri, 19 Jun 1998 15:10:13 GMT
From: John Porter <jdporter@min.net>
Subject: Re: subroutines
Message-Id: <358A810C.1437@min.net>
F.Quednau wrote:
>
> I believe the main
> difference between 'use' and 'require' is that with 'use something', the stuff
> in 'something' stays in its own namespace, and you have to 'import' stuff
> explicitly into your main:: namespace. 'require something' merely seems to add
> the stuff in 'something' to your main:: namespace. People, please correct me if
> I am wrong.
Yes, you are wrong. It's rather irresponsible to go and post an answer
like that, especially when you weren't even sure yourself.
In <6kvab9$lj5$1@csnews.cs.colorado.edu> on 1998/06/01
Tom Christiansen <tchrist@mox.perl.com> wrote:
> Succinctly:
>
> 1) do $file is like eval `cat $file`, except the former:
> 1.1: searches @INC.
> 1.2: bequeaths an *unrelated* lexical scope on the eval'ed code.
>
> 2) require $file is like do $file, except the former:
> 2.1: checks for redundant loading, slipping already loaded files.
> 2.2: raises an exception on failure to find, compile, or execute $file.
>
> 3) require Module is like require "Module.pm", except the former:
> 3.1: translates each "::" into your system's directory separator.
> 3.2: primes the parser to disambiguate class Module as an indirect object.
>
> 4) use Module is like require Module, except the former:
> 4.1: loads the module at compile time, not run-time.
> 4.2: imports symbols and semantics from that package to the current one.
--
John Porter
------------------------------
Date: Fri, 19 Jun 1998 16:37:32 +0100
From: "F.Quednau" <quednauf@nortel.co.uk>
Subject: Re: subroutines
Message-Id: <358A85BC.2EC5857D@nortel.co.uk>
John Porter wrote:
>
> F.Quednau wrote:
> > ... People, please correct me if
> > I am wrong.
>
> Yes, you are wrong. It's rather irresponsible to go and post an answer
> like that, especially when you weren't even sure yourself.
> [true answer]
> John Porter
Call it a ruthless exploitation of a very valuable resource (namely this
newsgroup). Having posted that I forced you (or someone else) to post the
correct answer. I consider myself burned and will not do it again.
--
____________________________________________________________
Frank Quednau
http://www.surrey.ac.uk/~me51fq
________________________________________________
------------------------------
Date: Fri, 19 Jun 1998 15:36:22 +0100
From: "Matthew Robertson" <mat.r@ukonline.co.uk>
Subject: Re: Subtracting Number of seconds from a date
Message-Id: <6mdt0u$hqr$1@morse.news.easynet.net>
The problem has been solved now.
Thanks to everyone for their help
Mat
------------------------------
Date: 19 Jun 1998 10:29:10 -0500
From: Jonathan Feinberg <jdf@pobox.com>
To: mjd@op.net (Mark-Jason Dominus)
Subject: Re: the ?PATTERN? match syntax
Message-Id: <ra0l5s1l.fsf@mailhost.panix.com>
mjd@op.net (Mark-Jason Dominus) writes:
> When is ?...? useful? What do you do with it?
It's terrific for obfuscation.
#!/usr/bin/perl -w -- Just another Perl hacker,
(open 0),$_=<0>,s,.*- +,,,chop;for(split?@*?){($$_++or$}=$_,y,y \,\
y,<STDIN>,,$$=~s\^\"sub $_ {print'$}'};7"\ee),y,} \,},>STDOUT,,&$_}
--
Jonathan Feinberg jdf@pobox.com Sunny Brooklyn, NY
http://pobox.com/~jdf/
------------------------------
Date: 19 Jun 1998 14:40:09 GMT
From: Tom Christiansen <tchrist@mox.perl.com>
Subject: Re: the ?PATTERN? match syntax
Message-Id: <6mdt89$ham$1@csnews.cs.colorado.edu>
[courtesy cc of this posting sent to cited author via email]
In comp.lang.perl.misc,
mjd@op.net (Mark-Jason Dominus) writes:
:When is ?...? useful? What do you do with it?
It captures its own state. You don't have
to say
if (!$matched && /pat/) {
$matched++;
# .....
}
You can just say:
if (?pat?) {
# .....
}
Which is much simpler. Likewise with the .. and ... flipflops. People
don't quite know what they're for, and they are for the same thing:
maintaining state without lots of extra variables. We don't *need* a
return statement in the language. We coud, of course, simply do the old
Pascal thing of needing extra variables and branches. But what a pain.
--tom
--
I dunno, I dream in Perl sometimes...
--Larry Wall in <8538@jpl-devvax.JPL.NASA.GOV>
------------------------------
Date: 8 Mar 97 21:33:47 GMT (Last modified)
From: Perl-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 8 Mar 97)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V8 Issue 2911
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