Hi Perl Monks,

I have DATA like this

__DATA__
Jun 12 09 mail (sender@sender.com) - (recip1@domain.com) 0.075 9387
Jun 12 10 mail (sender@sender.com) - (recip1@domain.com),(recip2@domai
+n.com) -1.889 25623
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How can I replace the pattern ( and ) in the 6 th field?

The OUTPUT I expect is

__DATA__
Jun 12 09 mail (sender@sender.com) - recip1@domain.com 0.075 9387
Jun 12 10 mail (sender@sender.com) - recip1@domain.com,recip2@domain.c
+om -1.889 25623
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the below code replaces all fields.

$_ =~ s/\(|\)//g; 
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Can I have something like this?

$_ =~ s/\(|\)//$f[6]g; 
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Your Ideas? Pls help me to slove this.

I'd like to migrate to Mojolicious, and would prefer to hear of ready to use plugins before reinventing the wheel... :)

Any recommendations?

I'm looking to detect a repeating sequence in a stream of data.

That is, given an essentially endless source of data that is known to eventually repeat; detect the start and length of the repeating sequence.

In simplistic terms, I want to program the equivalent of the algorithm that solve this regex: $str =~ m[(.+).*?(\1)]g;

Except that the values aren't characters or anything easily translated to characters and I cannot see the entire stream at any given time.

And the data stream and the length of the repeated sequence can be big. Very big. Likely bigger than I can hold in memory, so all of those Liv-Zempel windowed and sliding buffer compression algorithms go out of the window; as do any complex tree structures (trees/tries/graphs et. al).

The thought in my mind at the moment is (an adaption of) the rolling checksum algorithm used by rsync; but I'm not seeing how to apply it to my problem.

Any thoughts on that; or any pointers to any other algorithms that might be adaptable to this problem gratefully received.

Dear monks

I am creating a binary of my script for macOS using PAR pp (latest version). Is there a way to set the value of -mmacosx-version-min? Reason: pp seems to set it automatically to the OS version used to compile the binary. In this way, however, there are problems when running the same binary on older OS versions. The binary created with pp contains the following info (read with  $ otool -l binary):

Load command 9
      cmd LC_VERSION_MIN_MACOSX
  cmdsize 16
  version 10.13
      sdk 10.13
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In some circumstances (for example if the binary is bundled in a .app), macOS will refuse to run the binary if the OS is older than the version indicated here (at least this is what I 've understood with my researches until now). The pp instructions do not seem to mention any option.

The company I work for is considering putting some of its non-commercially-sensitive Perl modules on CPAN for general use. I have been asked to investigate this.

I already know about PAUSE and how to "Request PAUSE account" (I have such an account myself). The wisdom I'm seeking in this instance regards accounts for (commercial) organisations and whether there are any special considerations.

It looks like the process should be straightforward; but, of course, looks can be deceptive. If anyone has done this previously and encountered any stumbling blocks, gotchas, or such-like, a description of your experiences and how they were overcome (or, indeed, how to avoid them in the first place) would be much appreciated.

Thanks in advance.

I normally use two different versions of Perl on my computer: one that comes with the Linux distro (openSUSE) I use and another one that I use to write scripts and mess with, and that I normally compile myself from source. The reason I do this is to not introduce changes in the system's installation and potentially brake things beyond my knowledge on how to repair.

Until now I have done the quick & dirty procedure of just relying on my (usually more up to date) installation and neglect the system's Perl. However I realize that this is possibly not the soundest strategy. My question then is how should I best manage module installation and update using CPAN in these different installations?

The CPAN executables live in different folders and (I believe) are compiled to point to different sets of libraries. These executables can be called separately (/usr/bin/cpan; or /usr/local/bin/cpan). Now, CPAN requires a sort of environment (i.e. /root/.cpan/...). Both executables seem to use this same environment, but apparently these two CPAN realize the different upgrading needs (for example when calling "r").

How does this impact in the update of modules? Should I aim to create different CPAN work directories? Are there any recommendations out there on how to proceed with this?

Any hint will be appreciated.

Thanks in advance.

Hello everyone,

I have constructed this piece of code to illustrate three problems and I would like to know: How would you write this code so that it works?

Problem 1: The join is located at a problematic position due to the nature of how hashes work. Sometimes the code takes 6 seconds to execute and sometimes 2 + 6 seconds.

Problem 2: L2_counter1 => 3 is not incremented

Problem 3: (Is actually a question) Why do I need to use a share? The data is incremented independently, so I would think there should be no problems regards synchronicity. However if I don't use the share, nothing gets incremented at all...

Here is the code:

use strict ;
use warnings ;

use MCE::Hobo ;
use MCE::Shared ;

use Data::Dumper ;

sub task1 {
    print "Starting task 1 for $_[0]\n" ;
    sleep(2) ;
    print "Finished task 1 for $_[0]\n" ;
}

sub task2 {
    print "Starting task 2 for $_[0]\n" ;
    sleep(4) ;
    print "Finished task 2 for $_[0]\n" ;
}

sub task3 {
    print "Starting task 3 for $_[0]\n" ;
    sleep(6) ;
    print "Finished task 3 for $_[0]\n" ;
}

MCE::Hobo->init(
    max_workers => 2,
#     hobo_timeout => 10,
#     posix_exit => 1,
) ;

my $mutex = MCE::Mutex->new;

my $_test = {
    L1_counter1 => 1,
    # L1_counter2 => 2,
    # L1_counter3 => 3,
    nested1 => {
        L2_counter1 => 3,
        # L2_counter2 => 2,
        # L2_counter3 => 1,
    },
} ;

my $test ;
tie %{$test}, 'MCE::Shared', { module => 'MCE::Shared::Hash' }, %{$_te
+st} ;
print Dumper( $test ) ;

sub executeTasks {
    my $in = $_[0] ;
    my $hobo ;
    foreach( keys %{$in} ) {
        if ( ref $in->{ $_ } eq 'HASH' ) {
            executeTasks( $in->{ $_ } ) ;
        } else {
            if ( $in->{ $_ } == 1 ) {
                $hobo = mce_async {
                    task1( $_ ) ;
                    ++$in->{ $_ } ;
                } ;
            } elsif ( $in->{ $_ } == 2 ) {
                $hobo = mce_async {
                    task2( $_ ) ;
                    ++$in->{ $_ } ;
                } ;
            } elsif ( $in->{ $_ } == 3 ) {
                $hobo = mce_async {
                    task3( $_ ) ;
                    ++$in->{ $_ } ;
                } ;
            } ;
        } ;
    } ;
    $hobo->join() ;
} ;
executeTasks( $test ) ;
print "\n" ;
print Dumper( $test ) ;
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Hi guys , I need to move big databa among databases. I have been reading about improving performance with mysql prepared statements. So far I dont understand why it is better neither how to use it.
Lets suppose I have the following "bring and insert data" procedure:

#!/usr/bin/perl

use strict;
use warnings;
require DBI;

###
#variables here
my @big_data_array;
###

            foreach $id (@big_data_array){

                $query1 = "SELECT * from database1.table WHERE id = '$
+id'

                            my $sth1 = $dbh1->prepare($query1);
                            $sth2->execute();                    
                
                    while (my @row = $sth1->fetchrow_array ) {
                                                
                        $val1 = $row[0];
                        $val2=$row[1];
                        
                    }
                
                $query2 = "insert into database2.table ('value1','valu
+e2')".
                        " VALUES('$val1','$val2')";

                            my $sth2 = $dbh2->prepare($query2);
                            $sth2->execute();
                

            }

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Question is how to achieve same result using prepared statements ?
And why is it better ?
I will try to find more info about it. Regards, Leo.

I hope this isn't a stupid question, but at least I've discovered the solution to my problem, and I'm happy to share this story in the event that it helps someone else.

I've developed a pile of scripts that use Log::Log4perl, a module that I love to bits. Wanting to implement a system that would E-Mail me when there was a problem, I decided to add an E-Mail appender to my configuration. It worked fine in my test scripts, but didn't work in my work scripts, and I couldn't understand why.

I finally figured it out this afternoon (which will explain why I'm pausing to sip from my tall can of Waterloo Amber "Ontario's First Craft Brewery"). My test script looks like this:

{
  Log::Log4perl->init ( $log4perl_config );
  my $log = Log::Log4perl->get_logger();
  ..
  $log->info('Some stuff');
}
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my $log;
{
  Log::Log4perl->init ( $log4perl_config );
  $log = Log::Log4perl->get_logger();
  ..
  $log->info('Some stuff');
  do_something();
}
sub do_something
{
  $log->info('Some other stuff');
  ..
}
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See the difference? I'm using what I call a file scoped variable in the work script so that I don't have to pass the logger into the subroutine (something MSCHILLI goes 'Brrrr!' to here). I believe Log::Log4perl collects log entries to go out by E-Mail until the logger goes out of scope.

So the test script works fine. The work script's logger (I thought) would also go out of scope and send the E-Mail when the script finishes -- but no E-Mail is sent. Why not?

Anyway, my workaround is going to be to call get_logger in whichever scope I need to do logging. This works fine, but I'm left wondering why doesn't Log::Log4perl see that the logger has gone out of scope in the work script and send the E-Mail? Is there a 'finalize' or 'terminate' method I could have called to trigger this? Is this an error in the behaviour? (I find that hard to believe, for a module that's been around since 2002).

Does the Python syntax a = [0] * n; mean the same as Perl: @a = (0) x $n;?

Dual boot (i.e. same hardware), Ubuntu 17.10, Win10, threaded Perl 5.26 both. However, it seems some (default) flags (compiler options?) are set wrong for Inline::C on Windows. Here's output of no-op example for both systems:

$ perl -MTime::HiRes=time -MInline=C,'void foo(){}' -wE'$t=time;foo()f
+or 1..1e8;say time-$t'
5.57836294174194
$ perl -MTime::HiRes=time -wE'$t=time;sub foo(){}foo()for 1..1e8;say t
+ime-$t'
5.003093957901

>perl -MTime::HiRes=time -MInline=C,"void foo(){}" -wE"$t=time;foo()fo
+r 1..1e8;say time-$t"
11.325471162796

>perl -MTime::HiRes=time -wE"$t=time;sub foo(){}foo()for 1..1e8;say ti
+me-$t"
5.04568600654602

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The use of Inline::C for particular case, where I noticed that, is exactly for huge number of calls of very simple sub (but not no-op, of course). I understand sub calls in Perl are expensive, I'll live with that, but I don't understand the result above.

To counter "it's because Linux is better", the script was moved from very old 32-bit Windows machine, and I noticed (though can't provide any solid numbers right now), that benchmarks for pure-Perl parts showed perhaps 6-fold speed improvement, while the main part, in C, no more than 2-fold. Therefore I have a suspicion about sub-optimal Inline::C defaults there, and i hope for hints of what could be changed.

So, I wanted to understand the printf command and how to manipulate the formatting of a number (yes I am that new to this), namely how to insert a variable into %.f it would seem %.{$var}f does the trick.

And In this small script I thought I had it worked out

If I enter 1.111111111111111111111111111111 (1 with 30 1s after the decimal point) as an experimental value, when asked 'How many digits would you like after the decimal point ? ' if I answer 2 I get 1.11 as expected.

If I answer 10 I get 1.1111111111 as I would expect.

However if I answer 20 I get 1.11111111111111116045 (?)

And if I answer 30 I get 1.111111111111111160454356650007 (?)

Can someone tell me why please.

#! /usr/bin/perl -w

# experiment with printf

use strict;

my $num = 0;
my $dig = 0;

print 'Input a number :';
chomp( $num = <STDIN> );
print 'How many digits would you like after the decimal point ? ';
chomp( $dig = <STDIN> );
print "\n";
print 'Original number was ';
print "$num \n";
printf("And to $dig, points is ");
printf( "%.${dig}f", $num );
print "\n\n";

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echo 'display alert (do shell script "perl -v")' | osacompile -o perl.
+app

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• Process choices with Perl from an Applescript dialog to:
  1. Display output from Perl to an Applescript dialog.
  2. Execute Perl in Terminal to display its output.
  3. Send output from Perl to an application (TextExit).

• Other techniques covered here include:
  1. Visiting websites (Perlmonks of course!)
  2. Displaying notifications
  3. Application control
  4. Applescript subroutines
  5. Abusing buttons to widen dialogs
  6. How to rule your world with Perl!

(* Demonstration macOS/OSX app in AppleScript and Perl   *)
(* Posted to perlmonks.org by Anonymous Monk 6/14/2018   *)
(* Node: How to write apps for macOS/OSX in Perl! Part 2 *)

set TITLE to "Perl Version Tool"
set PROMPT to "Make a selection"
set _1 to "Perl version, patchlevel and license"
set _2 to "Perl configuration summary"
set _3 to "Perl command line help"
set _4 to "Visit Perlmonks.org!"

repeat
    set what to choose from list {_1, _2, _3, _4} with title TITLE wit
+h prompt PROMPT OK button name {"View"} cancel button name {"Exit"} d
+efault items _1
    set what to what as string
    
    if what is _1 then
        set CMD to "perl -v" # ONE LINERS OR PROGRAMS OF ANY SIZE!
        
    else if what is _2 then
        set CMD to "perl -V"
        
    else if what is _3 then
        set CMD to "perl -h"
        
    else if what is _4 then
        display notification "Opening The Monastery Gates!"
        set CMD to "open https://perlmonks.org"
        
    else if what is "false" then
        return # EXIT
        
    end if
    
    if what is _2 then
        # SEND PERL CODE TO TERMINAL AND EXECUTE
        doShell(CMD)
    else if what is _3 then
        # CAPTURE PERL STDOUT
        set CMD to do shell script CMD
        # SEND PERL STDOUT TO TEXTEDIT
        textEdit(CMD)
    else
        # CAPTURE PERL STDOUT
        set RES to do shell script CMD
        # MAKE DIALOG WIDE
        set SPC to "                                                  
+          "
        # PRINT PERL STDOUT TO APPLESCRIPT ALERT
        display alert TITLE message RES buttons {SPC & "Cool" & SPC} d
+efault button 1
    end if
end repeat

# APPLESCRIPT SUBS:

on doShell(CMD)
    try
        tell application "Terminal"
            activate
            tell application "System Events" to keystroke "n" using {c
+ommand down}
        end tell
        
        tell application "System Events"
            tell application process "Terminal"
                set frontmost to true
                keystroke CMD
                keystroke return
            end tell
        end tell
    on error oops
        display alert oops as critical
    end try
end doShell

on textEdit(CMD)
    try
        tell application "TextEdit"
            activate
            tell application "System Events" to keystroke "n" using {c
+ommand down}
        end tell
        
        tell application "System Events"
            tell application process "TextEdit"
                set frontmost to true
                keystroke CMD
            end tell
        end tell
    on error oops
        display alert oops as critical
    end try
end textEdit

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