Re: any ruby programmers who are perl users?
- Original Message - Whee! Inflammatory topic! 1) If you are interested in learning to program for the sake of programming (vs getting XYZ done), Perl probably isn't the best first choice. (Not that its the last choice or anything, but not first.) I'd personally advocate C/C++ or maybe Java. Maybe make Perl a third choice ;) Why? I use perl as my primary programming language and I've made web apps with it, desktop apps for Windows, portable desktop apps for Windows and Linux. If I don't need to work in a very big team of programmers and I don't need the programming language to force us all to use the same style and syntax, why should I use C++ or Java? Octavian -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Re: any ruby programmers who are perl users?
Octavian: Yitzle: 1) If you are interested in learning to program for the sake of programming (vs getting XYZ done), Perl probably isn't the best first choice. (Not that its the last choice or anything, but not first.) I'd personally advocate C/C++ or maybe Java. Maybe make Perl a third choice ;) Why? I use perl as my primary programming language and I've made web apps with it, desktop apps for Windows, portable desktop apps for Windows and Linux. If I don't need to work in a very big team of programmers and I don't need the programming language to force us all to use the same style and syntax, why should I use C++ or Java? Yitzle, who was dearly missing from the attribution section in your posting, mentioned Perl as not being his first choice for *learning* to program. Now read his reply again. -- Affijn, Ruud Gewoon is een tijger. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Re: sprintf format question
On Jun 4, 8:00 am, [EMAIL PROTECTED] (Rob Dixon) wrote:
April wrote:
sprintf( %s%$Fmt%s, (%$Fmt=|, $TestStr, |))
This is in Perl for Dummies, 4th ed, p160.
I'm trying to understand this ...
the first part, %s%$Fmt%s, my understanding is the format part,
which specifies the formats for the second part, thelist part, (%
$Fmt=|, $TestStr, |): %s for %$Fmt=|, %$Fmt for $TestStr, and %s
for |, respectively. Is this correct?
Then what is %$Fmt, it seems a % for format and then a variable $Fmt,
the book did not mention any format string like this ...
Anyone can shed some light? Thanks!
Hi April
The value of $Fmt will be interpolated into the double-quoted sting before it
is
used as a format. It needs to be one of the single-character format
conversion.
If you're not clear what I mean then try running this piece of code.
for my $Fmt ('s', 'd') {
print %s%$Fmt%s, \n;
}
HTH,
Rob- Hide quoted text -
- Show quoted text -
I understand now Rob, thanks!
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Re: Grep question
David Gilden schreef:
my $Comments = param('(Comments');
There is an extra '(' in there that you might not want.
Do you use Capitalization to show that the variable is initialised with
the value of a parameter?
Consider $p_comments or $param_comments or $param{Comments}.
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Gewoon is een tijger.
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Re: any ruby programmers who are perl users?
From: Dr.Ruud [EMAIL PROTECTED] Octavian: Yitzle: 1) If you are interested in learning to program for the sake of programming (vs getting XYZ done), Perl probably isn't the best first choice. (Not that its the last choice or anything, but not first.) I'd personally advocate C/C++ or maybe Java. Maybe make Perl a third choice ;) Why? I use perl as my primary programming language and I've made web apps with it, desktop apps for Windows, portable desktop apps for Windows and Linux. If I don't need to work in a very big team of programmers and I don't need the programming language to force us all to use the same style and syntax, why should I use C++ or Java? Yitzle, who was dearly missing from the attribution section in your posting, mentioned Perl as not being his first choice for *learning* to program. Now read his reply again. -- Affijn, Ruud Oh yes I'm sorry. I didn't understand it well. The problem is not the learning part, but using it for the sake of programming only. Perl it is also very good for learning, unless the programmer intends to learn some other programming languages. If someone starts with perl is very fine, but if that person will want to learn other programming languages, he might consider them all very strange and different, so Yitzle is right. Octavian -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Testing for a condition immediately after require
I want to be able to tag a module with one or more tags that can be tested for after requiring it. nbsp; require 'module'; lt;test for existence of tags in 'module'gt; nbsp; Any ideas on the best way to accomplish this? nbsp; Thanks in advance nbsp;
TCP apllications
Hi, This is Arun here, i am new to Perl so i was just thinking of programming the TCP apllications or working. So how do i do that, just needed guidance from you. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Re: TCP apllications
Arun wrote: Hi, This is Arun here, i am new to Perl so i was just thinking of programming the TCP apllications or working. So how do i do that, just needed guidance from you. A lot depends on how you want to use TCP, but take a look at perldoc -f socket and perldoc Socket HTH, Rob -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Re: TCP apllications
On Fri, Jun 6, 2008 at 7:29 PM, Arun [EMAIL PROTECTED] wrote: Hi, This is Arun here, i am new to Perl so i was just thinking of programming the TCP apllications or working. So how do i do that, just needed guidance from you. Licoln Stein's book Network Programming with Perl is great for you. -- Jeff Peng - [EMAIL PROTECTED] Professional Squid supports in China http://www.ChinaSquid.com/ -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Re: any ruby programmers who are perl users?
zentara wrote: On Thu, 05 Jun 2008 21:16:42 -0400, [EMAIL PROTECTED] (Richard Lee) wrote: Most likely just out of curiosity factor, I picked up a book Learning to program the facets of ruby series.. See what some experienced Perl programmers say about Ruby http://perlmonks.org?node_id=689996 zentara Hi, I read that and yes it is very helpful. I was just listening to podcasting and I heard Chad Fowler(my job went to india: 52 ways to save your job) talking about programming language in general. One of the quotes he says that I felt like it was for me was that, You really need to get out of your comfort zone time to time or else your comfort zone will be one of your limiting factor now I am still a beginner at perl but I have been using perl(I know no other programming languages) and I am really attached to the perl and wanted to get some other perspective and since I have been hearing so much about ruby.. perl is SO useful that (hmm how should I say, language itself and also the community) sometimes I lose sight on science of programming. I guess perl could be a bad language as first programming experince because perl just works so well and now that I have spend close to year, I find myself going backwards to learn some of whys and hows But now that I have spend close to year, I am really happy :-) I am not sure if learning another language while I am still newbie at my first language though. But giving that perl touches up on just too many areas, I feel like I should include another language just to get a fresh views... -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Re: any ruby programmers who are perl users?
yitzle wrote: 1) If you are interested in learning to program for the sake of programming (vs getting XYZ done), Perl probably isn't the best first choice. (Not that its the last choice or anything, but not first.) I'd personally advocate C/C++ or maybe Java. Maybe make Perl a third choice ;) I wonder why you say that? I have been programming in C and C++ for twenty years and in Perl for ten years. I also know a dozen other languages well, and have taught programming both in class and privately. Unless someone needs to know another language for a specific purpose I always recommend Perl, as most people - especially those who have never come across a programming language before - find it more intuitive than other languages. The obvious advantages for a learning language are - You write the code and run it: there is no compile/link/run cycle - It has a built-in debugger if you need one - Memory allocation is invisible, so there is no need to presize data structures - It handles all of the complex ideas like references and object orientation in with simple syntax conventions, and gives intelligible warnings instead of memory access violations - Finally, and above all, the Perl parser is highly oriented towards DWIM, which is ideally suited to people who learn programming - Perl puts you in control, and is friendly. When I teach C I find myself apologizing for the language and brusque error messages. Programmers are slapped for knowing only 95% of the language, and there is always confusion over whether an error is a compile, link, or run time fault. In contrast my Perl students feel encouraged by the compiler's error messages, as if it was the next step on a treasure trail. 2) If you are still picking up Perl and want to get into OOP, its probably better to stick with Perl and learn OOP rather than starting in on Ruby. The best way to learn OOP IMHO would be to come up (or get someone else to) with some sort of OOP project and then go ahead and implement it. I agree. Perl copies the way most languages implement object orientation but has very loose boundaries so that a mix of OO and procedural programming works fine. Most importantly, improper semantics often /do/ something instead of just throwing an error; that lets you see call chains and data flow, which leads to better understanding, even in faulty code. Perl has everything in place to allow people to use encapsulation, modularity, polymorphism and inheritance, but the mechanism is open and visible and that helps people understand what they are dealing with in similar circumstances in other languages. 3) Nope. Never did any Ruby. And there is the problem with improper quoting. Please include just as much of the post that you are responding to so that your own post makes sense in isolation. Rob -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Reg. Directory listing program
Hi,
Let me thank you for your help. I think you guys are doing a great work, its
really appreciative.
Thanks to David and John. Now that I changed my *perl* code to the
following, its actually working
*use strict;
use warnings;
use File::stat;
opendir (DH, subcode) or die $!;
chdir(C:/Documents and Settings/Myself/Desktop/code/subcode);
foreach my $file(readdir DH)
{
my $value=stat($file);
my $perm=$value-mode 0;
printf \n$file\t%04o\n, $perm;
}
closedir (DH);*
Leading to a question, why did we 'AND' *mode* to *0*. What does each
bit stand for and why there are 5 bits as compared to UNIX's
User-Group-Others bits. So actually 3 questions :)
Thank you.
--
Gunwant Singh
History:
---
Hi,
I am new to this mailing list and I am very new to PERL. So, please bear
with me for my questions.
I wrote a code that lists files in a directory with the permissions. I am
coding for MS-Windows.
Here is my code:
1 use strict;
2 use warnings;
3 use File::stat();
4
5 opendir (DH, subcode) or die $!;
6 foreach my $file(readdir DH)
7 {
8 my $perm=stat($file)-mode;
9 print $file\t$perm\n;
10 }
11 closedir (DH);
I am getting the listing of file just fine if I dont add line 8. But as soon
as I try to display the permissions, I get this:
Can't call method mode without a package or object reference at
C:\Documents a
nd Settings\Myself\Desktop\code\dir-op.pl line 8.
What am I doing wrong!
Thanks.
--
Gunwant Singh
---
-Original Message-
From: Gunwant Singh [mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 04, 2008 10:02
To: beginners@perl.org
Subject: Reg. Directory listing program
Hi,
I am new to this mailing list and I am very new to PERL. So,
please bear
with me for my questions.
I wrote a code that lists files in a directory with the
permissions. I am
coding for MS-Windows.
Here is my code:
*1 use strict;
2 use warnings;
3 use File::stat();
4
5 opendir (DH, subcode) or die $!;
6 foreach my $file(readdir DH)
7 {
8 my $perm=stat($file)-mode;
you need something like:
my $filestat = stat($file);
my $perm=$filestat-mode;
but this will not work correctly unless you are already positioned on
the right directory location. So either you can do a chdir to the folder
you are doing or a concatenate of subcode . $file to get the file
status correctly.
Wags ;)
9 print $file\t$perm\n;
10 }
11 closedir (DH);
*I am getting the listing of file just fine if I dont add
line 8. But as
soon as I try to display the permissions, I get this:
*Can't call method mode without a package or object reference at
C:\Documents a
nd Settings\Myself\Desktop\code\dir-op.pl line 8.
*What am I doing wrong!
Thanks.
--
Gunwant Singh
---
-Original Message-
From: Wagner, David --- Senior Programmer Analyst --- WGO
[mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 04, 2008 11:08
To: Gunwant Singh; beginners@perl.org
Subject: RE: Reg. Directory listing program
-Original Message-
From: Gunwant Singh [mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 04, 2008 10:02
To: beginners@perl.org
Subject: Reg. Directory listing program
Hi,
I am new to this mailing list and I am very new to PERL. So,
please bear
with me for my questions.
I wrote a code that lists files in a directory with the
permissions. I am
coding for MS-Windows.
Here is my code:
*1 use strict;
2 use warnings;
3 use File::stat();
4
5 opendir (DH, subcode) or die $!;
6 foreach my $file(readdir DH)
7 {
8 my $perm=stat($file)-mode;
you need something like:
my $filestat = stat($file);
my $perm=$filestat-mode;
I was looking at Programming Perl and if you want to make sense
of the mode, then should 'and' with 0 and print out using %04o (
octal output ), so something like:
my $perm=$filestat-mode 0;
but this will not work correctly unless you are already positioned on
the right directory location. So either you can do a chdir to
the folder
you are doing or a concatenate of subcode . $file to get the file
status correctly.
Wags ;)
9 print $file\t$perm\n;
Then change print to
printf $file %04o\n, $perm;
Wags ;)
10 }
11 closedir (DH);
*I am getting the listing of file just fine if I dont add
line 8. But as
soon as I try to display the permissions, I get this:
*Can't call method mode without a package or object reference at
C:\Documents a
nd Settings\Myself\Desktop\code\dir-op.pl line 8.
*What am I doing wrong!
Thanks.
--
Gunwant Singh
**
This message contains information that is confidential and
proprietary to FedEx Freight or its affiliates. It is
intended only for the recipient named and for the
Re: Can not get reliable output [WAS Reg. Directory listing program]
Michelle Konzack wrote:
Hello,
Hello,
I have a similar problem but with mode which output weird permissions:
[ '~/bin/.perl_test_001' ]--
#!/usr/bin/perl
use strict;
use warnings;
use File::stat;
opendir(DH, /home/michelle.konzack/bin) || die $!;
my @dir=readdir DH;
foreach (@dir)
{
my $FILE=$_;
my $FILESTAT=stat(/home/michelle.konzack/bin/ . $_);
my $MODE=$FILESTAT-mode;
printf %-30s%s\n, $FILE, $MODE;
}
and the output is something like:
[ command '.perl_test_001' ]
snip
.perl_test_00133279
[snip]
where perl_test_001 has mode 0777.
Whats wrong here?
$ perl -le'printf %o\n, 33279'
100777
33279 is the decimal representation of a number, and 0777 is the octal
representation of a number. If a number has a leading zero it is
usually displayed in octal representation.
$ perl -le'print for 0777, 777'
511
777
So 0777 is the octal representation of the decimal number 511.
Perl can display numbers in either decimal, hexadecimal, octal or binary
formats:
$ perl -le'printf %1\$#d%1\$#x%1\$#o%1\$#b\n, 777'
7770x309014110b111001
Perl can also use literal numbers represented in either decimal,
hexadecimal, octal or binary formats:
$ perl -le'printf %s%s%s%s\n, 777, 0x309, 01411, 0b111001'
777777777777
What I do not understand is:
[ perldoc 'File::stat' ]
BUGS
As of Perl 5.8.0 after using this module you cannot use the
implicit $_ or the special filehandle _ with stat() or
lstat(), trying to do so leads into strange errors. The
workaround is for $_ to be explicit
my $stat_obj = stat $_;
That is not related to your problem.
John
--
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order.-- Larry Wall
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Re: Reg. Directory listing program
Gunwant Singh wrote:
Hi,
Hello,
Let me thank you for your help. I think you guys are doing a great work, its
really appreciative.
Thanks to David and John. Now that I changed my *perl* code to the
following, its actually working
*use strict;
use warnings;
use File::stat;
opendir (DH, subcode) or die $!;
chdir(C:/Documents and Settings/Myself/Desktop/code/subcode);
foreach my $file(readdir DH)
{
my $value=stat($file);
my $perm=$value-mode 0;
printf \n$file\t%04o\n, $perm;
}
closedir (DH);*
Leading to a question, why did we 'AND' *mode* to *0*. What does each
bit stand for and why there are 5 bits as compared to UNIX's
User-Group-Others bits. So actually 3 questions :)
man 2 stat
[snip]
The following flags are defined for the st_mode field:
S_IFMT 017 bitmask for the file type bitfields
S_IFSOCK 014 socket
S_IFLNK012 symbolic link
S_IFREG010 regular file
S_IFBLK006 block device
S_IFDIR004 directory
S_IFCHR002 character device
S_IFIFO001 FIFO
S_ISUID0004000 set UID bit
S_ISGID0002000 set-group-ID bit (see below)
S_ISVTX0001000 sticky bit (see below)
S_IRWXU00700 mask for file owner permissions
S_IRUSR00400 owner has read permission
S_IWUSR00200 owner has write permission
S_IXUSR00100 owner has execute permission
S_IRWXG00070 mask for group permissions
S_IRGRP00040 group has read permission
S_IWGRP00020 group has write permission
S_IXGRP00010 group has execute permission
S_IRWXO7 mask for permissions for others (not
in group)
S_IROTH4 others have read permission
S_IWOTH2 others have write permission
S_IXOTH1 others have execute permission
So mode 0 displays the permission bits as well as SUID, SGID and
the sticky bit.
John
--
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order.-- Larry Wall
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Re: TCP apllications
Hi Arun You didn't say what you really wanted to achieve. Do yo want to dabble and learn from that experience what using network modules is all about ? -- Andrew Edinburgh,Scotland On Fri, 6 Jun 2008, Arun wrote: Hi, This is Arun here, i am new to Perl so i was just thinking of programming the TCP apllications or working. So how do i do that, just needed guidance from you. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Re: pie multiline replace
Richard Lee wrote:
Gunnar Hjalmarsson wrote:
perldoc -q insert a line
Within that basic form, add the parts that you need to insert, change,
or delete lines.
To prepend lines to the beginning, print those lines before you enter
the loop that prints the existing lines.
open my $in, '', $file or die Can't read old file: $!;
open my $out, '', $file.new or die Can't write new file: $!;
print # Add this line to the top\n; # --- HERE'S THE MAGIC
while( $in )
{
print $out $_;
}
close $out;
I was just going over this... but shouldn't it be
print $out # Add this line to the top\n; # ??? or did I miss
something?
I think you are right. I'd suggest that you send a note to Brian d'Foy
([EMAIL PROTECTED]), who is maintaining the FAQ.
--
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Email: http://www.gunnar.cc/cgi-bin/contact.pl
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Re: pie multiline replace
Gunnar Hjalmarsson wrote: close $out; I was just going over this... but shouldn't it be print $out # Add this line to the top\n; # ??? or did I miss something? I think you are right. I'd suggest that you send a note to Brian d'Foy ([EMAIL PROTECTED]), who is maintaining the FAQ. done, and thanks for confirming. I was just afraid that I have missed something while reading that faq lines.. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
Looping through an anonymous array of arrays
my $arrayRef = [ 1, 2, 3, ['a', 'b', 'c', [Hello] ]]; I have no problem returning single elements but how would one walk this list of elements with say a for loop?
Re: Looping through an anonymous array of arrays
On Sat, Jun 7, 2008 at 9:31 AM, Rodrick Brown [EMAIL PROTECTED] wrote:
my $arrayRef = [ 1, 2, 3, ['a', 'b', 'c', [Hello] ]];
I have no problem returning single elements but how would one walk this list
of elements with say a for loop?
Try this code:
use strict;
my $arrayRef = [ 1, 2, 3, ['a', 'b', 'c', [Hello] ]];
lookinto($arrayRef);
sub lookinto {
my $obj = shift;
if (ref $obj) {
for (@$obj) {
lookinto($_);
}
} else {
print $_\n;
}
}
--
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Professional Squid supports in China
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Re: Looping through an anonymous array of arrays
On Fri, Jun 6, 2008 at 9:31 PM, Rodrick Brown [EMAIL PROTECTED] wrote:
my $arrayRef = [ 1, 2, 3, ['a', 'b', 'c', [Hello] ]];
I have no problem returning single elements but how would one walk this list
of elements with say a for loop?
You can treat an array reference like an array by prefixing it with an
@ (this is called dereferencing):
for my $item (@$arrayRef) {
if (my $type = ref $item) {
print item is a $type reference\n;
} else {
print item is $item\n;
}
}
If you just want to print out the items held in the data structure you
can use a recursive function:
sub print_it {
for my $item (@_) {
if (ref $item) {
print_it(@$item);
next;
}
print $item ;
}
}
print_it($arrayRef);
--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
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Re: Looping through an anonymous array of arrays
Rodrick Brown wrote:
my $arrayRef = [ 1, 2, 3, ['a', 'b', 'c', [Hello] ]];
I have no problem returning single elements but how would one walk this list
of elements with say a for loop?
One way:
my $level = 0;
breakdown( $arrayRef );
sub breakdown {
my $ref = shift;
foreach my $elem ( @$ref ) {
if ( ref($elem) eq 'ARRAY' ) {
$level++;
breakdown( $elem );
$level--;
} else {
print \t x $level, $elem\n;
}
}
}
But as usual when we are dealing with nested data structures,
Data::Dumper comes in handy:
use Data::Dumper;
print Dumper $arrayRef;
--
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Email: http://www.gunnar.cc/cgi-bin/contact.pl
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