[22030] in Perl-Users-Digest
Perl-Users Digest, Issue: 4252 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Thu Dec 12 00:10:37 2002
Date: Wed, 11 Dec 2002 21:10:11 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Wed, 11 Dec 2002 Volume: 10 Number: 4252
Today's topics:
Re: Simplify split and s/// statement <krahnj@acm.org>
Re: Simplify split and s/// statement (Tad McClellan)
Re: Simplify split and s/// statement <mgjv@tradingpost.com.au>
Re: Telnet using "character mode" for modem control <jay@rgrs.com>
Re: what perl calls is the challenge <xxxxxxx@xxx.xxx>
Re: what perl calls is the challenge <bobx@linuxmail.org>
Re: what perl calls is the challenge (Tad McClellan)
Re: Why doesn't my array grow? <bstutes@eskimo.com>
Windows to Unix Net::SCP or SFTP, public key authentica (Daveo)
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Thu, 12 Dec 2002 01:39:02 GMT
From: "John W. Krahn" <krahnj@acm.org>
Subject: Re: Simplify split and s/// statement
Message-Id: <3DF7E888.2E78B17@acm.org>
Alexander Stremitzer wrote:
>
> I am using the following code segment in my program. The code does what
> it is supposed to do. However, it looks somewhat cludgy.
> Is there a way to simplify the statement below ? The goal is to remove
> the trailing white space from all fields.
>
> my ($pat_name,$pat_id,$birth_date,$accnbr,$study_date) = split (/\|/,
> $PDS_LINE);
> $pat_name =~ s/\s*$//; # remove trailing white space
> $pat_id =~ s/\s*$//; # remove trailing white space
> $birth_date =~ s/\s*$//; # remove trailing white space
> $accnbr =~ s/\s*$//; # remove trailing white space
> $study_date =~ s/\s*$//; # remove trailing white space
>
> __DATA__
> Patient name |patient id |1926.02.02|123456789
> |2002.10.12
my ($pat_name,$pat_id,$birth_date,$accnbr,$study_date) = split /\s*\|\s*/, $PDS_LINE;
John
--
use Perl;
program
fulfillment
------------------------------
Date: Wed, 11 Dec 2002 21:16:54 -0600
From: tadmc@augustmail.com (Tad McClellan)
Subject: Re: Simplify split and s/// statement
Message-Id: <slrnavfvt6.37o.tadmc@magna.augustmail.com>
Alexander Stremitzer <stremitz@consultant.com> wrote:
> I am using the following code segment in my program. The code does what
> it is supposed to do. However, it looks somewhat cludgy.
> Is there a way to simplify the statement below ? The goal is to remove
> the trailing white space from all fields.
>
> my ($pat_name,$pat_id,$birth_date,$accnbr,$study_date) = split (/\|/,
> $PDS_LINE);
foreach ( $pat_name, $pat_id, $birth_date, $accnbr, $study_date ) {
s/\s+$//;
}
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: Thu, 12 Dec 2002 04:23:57 GMT
From: Martien Verbruggen <mgjv@tradingpost.com.au>
Subject: Re: Simplify split and s/// statement
Message-Id: <slrnavg3uf.865.mgjv@verbruggen.comdyn.com.au>
On Wed, 11 Dec 2002 17:33:04 -0500,
Alexander Stremitzer <stremitz@consultant.com> wrote:
> I am using the following code segment in my program. The code does what
> it is supposed to do. However, it looks somewhat cludgy.
> Is there a way to simplify the statement below ? The goal is to remove
> the trailing white space from all fields.
>
> my ($pat_name,$pat_id,$birth_date,$accnbr,$study_date) = split (/\|/,
> $PDS_LINE);
Just to add another possibility:
my ($pat_name,$pat_id,$birth_date,$accnbr,$study_date) =
map { s/\s+$// } split (/\|/, $PDS_LINE);
I like map for the readability of the code.
Martien
--
|
Martien Verbruggen | For heaven's sake, don't TRY to be cynical.
Trading Post Australia | It's perfectly easy to be cynical.
|
------------------------------
Date: 11 Dec 2002 18:16:33 -0500
From: Jay Rogers <jay@rgrs.com>
Subject: Re: Telnet using "character mode" for modem control
Message-Id: <828yywcfji.fsf@shell2.shore.net>
Milan <me@planet-earth.com> writes:
> Does anyone know of a way to make the Net::Telnet modules use
> "character" mode instead of "line" mode. I have checked the
> documentation but cannot find anything about this.
This is item from the section "What To Know Before Using" of the
Net::Telnet doc may be helpful:
. The output record separator for print() and cmd() is set
to "\n" by default, so that you don't have to append all
your commands with a newline. To avoid printing a
trailing "\n" use put() or set the output_record_separator
to "".
--
Jay Rogers
jay@rgrs.com
------------------------------
Date: Thu, 12 Dec 2002 00:29:28 GMT
From: "Brad" <xxxxxxx@xxx.xxx>
Subject: Re: what perl calls is the challenge
Message-Id: <ILQJ9.18518$y14.1658330@news1.east.cox.net>
"Eric Osman" <os7man@attbi.com> wrote in message
news:3DF7B95E.D32CE1FC@attbi.com...
>
> Hi,
>
> My challenge seems to be with the things my perl
> script is calling, rather than perl itself.
>
> So, when you read this question and feel I need to
> be asking "elsewhere" and you can suggest a useful
> newsgroup, please let me know.
>
> I'm having trouble getting the following perl (excerpt
> only shown) to work :
>
> #!/usr/bin/perl
> %postInputs = readPostInput();
> $dateCommand = "date";
> $time = `$dateCommand`;
> open (MAIL, "|/usr/sbin/sendmail -t") || return 0;
> select (MAIL);
> . . .
>
> This example is suggested in "writing your first program"
> in my perl book. If you want to see the entire
> program, it's on this web page :
>
> ftp://ftp.sybex.com/2200/Perllist1.pdf
>
> My environment is windows 98 with indigoperl .
The main problem is that you are using Windows 98, and the sendmail command
is a UNIX command. This is not what I would call a "first" program to use.
INot sure why it would be listed as one either. I'm sure there are perl
books out there for the Windows users.
Brad
------------------------------
Date: Thu, 12 Dec 2002 00:35:23 GMT
From: "Bob X" <bobx@linuxmail.org>
Subject: Re: what perl calls is the challenge
Message-Id: <fRQJ9.1521$uV4.1158683@news2.news.adelphia.net>
http://www.oreilly.com/catalog/lperlwin/
------------------------------
Date: Wed, 11 Dec 2002 20:39:15 -0600
From: tadmc@augustmail.com (Tad McClellan)
Subject: Re: what perl calls is the challenge
Message-Id: <slrnavftmj.2jd.tadmc@magna.augustmail.com>
Eric Osman <os7man@attbi.com> wrote:
> My challenge seems to be with the things my perl
> script is calling, rather than perl itself.
Your challenge is really that you are using a very poor
source of information.
> I'm having trouble getting the following perl (excerpt
> only shown) to work :
>
> #!/usr/bin/perl
> %postInputs = readPostInput();
> $dateCommand = "date";
> $time = `$dateCommand`;
> open (MAIL, "|/usr/sbin/sendmail -t") || return 0;
> select (MAIL);
> . . .
>
> This example is suggested in "writing your first program"
> in my perl book.
What Perl book is that?
Does it have a title and author?
(time passes...)
Oh. It appears to be "Mastering Perl 5" by Eric C. Herrmann.
Is that the one?
> If you want to see the entire
> program, it's on this web page :
>
> ftp://ftp.sybex.com/2200/Perllist1.pdf
That is not a web page. Web pages use the hypertext transfer
protocol (HTTP), not the file transfer protocol (FTP).
> My environment is windows 98 with indigoperl .
>
> I'll present my MAIN challenge first, then a more
> minor one.
>
> The main one is with
>
> open (MAIL, "|/usr/sbin/sendmail -t") . . .
> I'm sure "sendmail" is standard on unix systems, but
> should I be using something else in indigoperl on
> windows 98 ?
I expect so, but I can't help with that because I don't do Windows.
Your anonymous "perl book" appears to assume that you are
on a Unix system.
(time passes...)
Err, except he also uses `dir/w`...
> Or am I supposed to be installing "sendmail" from
> some independently different place ? (what do you
> suggest ?) .
The author does not know Perl very well.
The author is not a very good teacher.
I suggest selling the book to a sucker on Ebay and getting
a Real Book. :-)
> The more minor challenge is with this morsel:
>
> $dateCommand = "date";
> $time = `$dateCommand`;
>
>
> That was HANGING my script, because on windows 98,
> the "date" command not only displays the date but asks
> you to type in a new one !!!!
> What should I be using instead.
The author of the "book" should have used something else instead.
He inserted a system dependency when he didn't need to, he could
have gotten what he wanted using only native Perl:
my $time = localtime;
> Thanks for any ideas.
Your book sucks. Ditch it before you learn more bad habits.
Below are some examples of its suckiness:
no warnings
no strictures
no CGI.pm on any of the programs shown!
barewords galore
ignores perlstyle.pod
uses select() for few print()s
-----
Confuses folks right off the bat with alternative quoting
delimiters, when it doesn't have to:
book:
print qq|The value of $key is $ENV{"$key"}\n|;
better:
print "The value of $key is $ENV{$key}\n";
Since this code is labeled as "Listing 1.1" I assume it is
the very first code that readers are exposed to?
-----
More unnecessary complexity:
book:
select (MAIL);
print << "EOF"; <== useless double quotes
...
EOF
select (STDOUT);
better:
print MAIL << EOF;
...
EOF
-----
So far they have just been presented badly, this one
is a plain bug!
The purpose of file locking is to avoid data corruption due to
a "race condition", this code _has_ a race condition, the very
thing it supposed to be protecting against.
flock(OUTFILE, LOCK_UN)|| warn $!; <== delete this line of code
close (OUTFILE);
-----
@carMakes = (Mitsubishi, Geo, Chevrolet, Ford);
Bare words are bad. Strings should be quoted.
-----
C code, written in Perl:
book:
for ($index = 0; $index <= $#inventory; $index++){
better:
for $index ( 0 .. $#inventory ) {
-----
You should always, yes *always*, check the return value from open().
book:
open (STOREINV, "$store${num}.txt");
^ ^
^ ^ useless use of curlies
better:
open(STOREINV, "$store$num.txt") or
die "could not open '$store$num.txt' $!";
-----
perlvar.pod says "Its use is highly discouraged."
$[ = 1501;
so the author should not be teaching/recommending it.
-----
Uses the dollar-digit variables without first testing
for a successful match.
book:
$totalDue =~ /(\d*\.\d\d)/;
$truncatedValue = $1;
better:
if ( $totalDue =~ /(\d*\.\d\d)/ ) {
$truncatedValue = $1;
}
(and he appears to not understand accuracy and precision issues
of floating point numbers...
)
-----
Gak! Teaches symrefs to beginners!
Symrefs are for experts only.
Listing 7.1: Symbolic References
-----
Errr, _which_ parenthesis?
book:
#Note that the parentheses are REQUIRED
($s, $st, $segmentComment) = split(' ',$line,3);
just as good:
($s, $st, $segmentComment) = split ' ', $line, 3;
--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas
------------------------------
Date: Wed, 11 Dec 2002 22:59:25 -0600
From: Bob Stutes <bstutes@eskimo.com>
Subject: Re: Why doesn't my array grow?
Message-Id: <at953l$37e$1@eskinews.eskimo.com>
Rob Richardson wrote:
> Greetings!
>
> I am trying to generate a calendar. Since a calendar can conceivably
> require 6 rows of 7 cells each, I am trying to create a 42-element
> array. Those cells that represent valid dates will get the date in a
> string format. Those that don't represent dates will get an empty
> string. Here's the code:
>
> sub calendar
> {
> <initialization code snipped>
>
> # Create a 42-element array starting at the start index.
> # @calendar = ($startIndex .. $startIndex + 42);
> @calendar = ();
> # for ($i = $startIndex; $i < ($startIndex + 42); $i++)
> for ($i = 0; $i < 42; $i++)
> {
> $currentIndex = $startIndex + $i;
> if ($currentIndex < 1 || $currentIndex > $daysInThisMonth)
> {
> $calendar[currentIndex] = ""
> }
> else
> {
> $calendar[currentIndex] = "$actualMonth.$currentIndex.$actualYear"
> }
> print "Index: $currentIndex; contents: $calendar[currentIndex]! <BR>"
> }
>
> $arraySize = @calendar;
make this line: $arraySize = $#calendar;
see perldata documentation.
> print "Before returning from subroutine, calendar has $arraySize
> elements. <BR>";
> return @calendar;
> }
>
> I'm a newbie in Perl, but I understand that arrays are supposed to
> grow if you write to an element beyond the current end of the array.
> The print statement that reports the contents of the cells shows that
> the cells are being populated as expected. But the print statement
> that reports the size of the array says the array only has one
> element! What don't I know yet?
>
> Thanks!
>
> Rob
--
Bob Stutes - St. Louis, Mo.
Unix Administrator and General Geek Wanna-Be
e-mail: bstutes@eskimo.com
The Wisdom of the ages may be found ... if you will only look up.
Unknown.
------------------------------
Date: 11 Dec 2002 15:07:06 -0800
From: david.c.obrien@citigroup.com (Daveo)
Subject: Windows to Unix Net::SCP or SFTP, public key authentication question
Message-Id: <7b343fef.0212111507.b2f889f@posting.google.com>
I am trying to establish a SSH connection from Windows to a Unix host
via Net::SCP. The module allows public key authentication. I know
that I put the public key in the ~username/.ssh/authorized_keys file,
and I can get this to work with the Putty Windows SSH client (using
the puttygen.exe program to generate the private and public keys).
My question(s) is how do I generate a set of keys, for use with
Net::SCP/SFTP?
Once generated, where do I put them, so they can be used (on the
client side)?
I have done a pretty thorough google search for this, and read the
ssh-keygen man pages etc, but most of these assume you are doing a
Unix-Unix transfer.
A few people mention they have done this, but don't mention how they
managed the client side key generation/handling.
thanks
Dave
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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------------------------------
End of Perl-Users Digest V10 Issue 4252
***************************************
