Perl Weekly Challenge # 8: Perfect Numbers and Centered Output

These are some answers to the Week 8 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Challenge # 1: Perfect Numbers

Write a script that computes the first five perfect numbers. A perfect number is an integer that is the sum of its positive proper divisors (all divisors except itself). Please check Wiki for more information. This challenge was proposed by Laurent Rosenfeld.

Perl Weekly Challenge 007: Niven Numbers and a Word Ladder

I know I’m late with my blog post. I had the solutions ready in time, but I suffered a dental abscess and spent the rest of the week either praying for the painkillers to kick in or sleeping when they did.

How I Spent My Perl Toolchain Summit v2019

I was fortunate to be able to attend the Perl Toolchain Summit again this year. The MetaCPAN team worked hard. I've tried to summarize our efforts with this post.

Reddit: After 2020, European Perl conferences are over

This popped up on Reddit, I don't go there much either, but the crowd here might want to read get involved in the dicussion:

Quote:

Perl Weekly Challenge # 7: Niven Numbers and Word Ladders

These are some answers to the Week 7 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Challenge # 1: Niven Numbers

Print all the niven numbers from 0 to 50 inclusive, each on their own line. A niven number is a non-negative number that is divisible by the sum of its digits.

A Niven number or harshad number is a strictly positive integer that can be evenly divided by the sum of its digits. Note that this property depends on the number base in which the number is expressed (the divisibility property is intrinsic to a pair of numbers, but the sum of digits of a given number depends on the number base in which the number is expressed). Here we will consider only numbers in base 10.

Please also note that 0 cannot be a divisor of a number. Therefore, 0 cannot really be a Niven number. We'll start at 1 to avoid problems.

Niven Numbers in Perl 5

Renaming modules from the command line

As we continue to build Tau Station, the free-to-play narrative sci-fi MMORPG (what a mouthful!), we find our code base is getting larger and larger. As with any large codebase, we've found ourselves sometimes mired in technical debt and need a way out.

One simple hack I wrote has saved so much grief with this process. I can run this from the command line:

bin/dev/rename-module.pl Veure::Old::Module::Name Veure::New::Module::Name

And it automatically renames the module for me, updates all references to it, creating directories as needed, renaming test classes built for it, and uses git.

Daily CPAN upload chain broke, again !!!

Yesterday was the saddest day for me as the daily CPAN upload chain was broken again. It reminded me of the day when it happened last time when I was on 1027 days. It was the first day of my holiday in India. It was easier to cope with the heartbreak that time as I was with my parents. Like always, I had delegated the uploading task to my younger brother, who lives in Pune, India. But for some reason, he forgot to upload the tarball and when he realised it was too late.

Around 12:15pm yesterday I was about to do routine daily upload to CPAN. I immediately got "Internal Server Error" first. I have never ever seen that error before. Not sure what to do, I jumped on Twitter and asked for any advise.

Olaf Alders responded first and suggested to reach out to #toolchain (IRC).

Little later Neil Bowers replied that he contacted Andreas and Perl NOC team by email.

Perl Toolchain Summit 2019 report

The Perl Toolchain Summit (previously known as the Perl QA Hackathon) is an annual coding workshop for people involved in the Perl toolchain, testing, quality assurance, and related issues. I was glad to be invited to this one, my fourth.

Wildcard Unicode Property Values

In addition to Native Variable-Length Lookbehind, Perl 5.29.9 (sic) includes another Regexp enhancement: wildcard Unicode property values. (And yes, this blog post sat around in draft form for over a month.)

Despite its name, the implementation is in terms of regular expressions rather than traditional wildcards. An example may be better than an explanation here: instead of writing /[\p{Script=Latin}\p{Script=Greek}]/, the new feature allows you to write /\p{Script=<\A(Latin|Greek)\z>}/. This is, according to perlunicode, a partial implementation of the Unicode Consortium's Wildcards in Property Values. Something like /\p{<Latin|Greek>}/ will not work, nor will /\p{Is_<Latin|Greek>}/; you must specify property name = ... to access this functionality.

Note the need for anchors in the above example. Something like /\p{Script=<ee>}/ would match any script whose name contained a double "e".

Perl Weekly Challenge # 6: Ramanujan's Constant

These are some answers to Challenge 2 of the Week 6 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Challenge 1 (compact numeric ranges) was covered in this post.

Challenge 2 was as follows:

Create a script to calculate Ramanujan’s constant with at least 32 digits of precision. Find out more about it here (Wikipedia link).

The Wikipedia link provided in the question concerning this second challenge was apparently changed some time after the challenge was initially posted.

The original link, posted on Monday, April 29, 2019, was pointing to the Landau-Ramanujan Constant, which relates to the sum of two squares theorem.

Then, two days later, on May 1, 2019, I noticed that the link had changed and pointed towards this other Wikipedia page about Ramanujan's constant, which refers to irrational (well, in this case, actually transcendental) numbers that almost look like integers. I do not know when exactly the Wikipedia link was changed.

Monitorix 3.11.0 released

Another great Perl software that I find very useful is Monitorix.

Monitorix is FOSS lightweight system monitoring designed to monitor as many services and system resources as possible.

system.png

The tl;dr is that it works really well for monitoring stand alone machines- which is what I used it for. It's tracks all sorts of metrics with minimal configuration by me, and with packages for most distros its trivial to install and update.

Version 3.11.0 was released in March with new features and fixes.

Try it for yourself at Monitorix.org and at Github

Monthly Report - April

Last month was mostly dedicated to the "Perl Weekly Challenge". It took most of my spare time and because of that I had to delay my other pet project "London Hack Day". I promise to get it going soon. The "Perl Weekly Challenge" is now settling down quite well. I have had positive feedback so far. We now have 77 active members. It is also becoming popular on Twitter as we now have 117 followers with over 300+ tweets. It is nice to see how Perl5 and Perl6 communities worked on this project without any issues. If you have time then please take a look at the Knowledge Base.

Let's take a quick look through last month main activities.

  • Pull Request
  • Git Commits
  • Perl Weekly Challenge
  • Pull Request Club
  • Perl Blog
  • PerlWeekly Newsletter
  • Adopt CPAN Module

Pull Request

60 Pull Requests submitted in the month of April. With this I have now completed 50+ Pull Request every month so far in the year 2019, one of my new year resolutions.

Overall 1701 Pull Request altogether.

Perl Weekly Challenge 006: Ranges and Ramanujan's Constant

This week, after having read the tasks, I decided to demonstrate the power of CPAN. There already are modules that solve the problems, so the only skill you need is the art of searching CPAN.

Perl Weekly Challenge # 6: Compact Number Ranges

These are some answers to the Week 6 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler alert: this post reveals breaking details about the plot of forthcoming episodes of Game of Thrones. Oops, no, that's not what I meant to say. As of this writing, the Perl Weekly Challenge # 6 is still going until Sunday May 10, 2019, please don't read on if you intend to solve the challenge by yourself.

The Wikipedia link provided in the question concerning the second challenge (Ramanujan's Constant) was apparently changed some time after the challenge was initially posted. I worked on the original link (and the Landau-Ramanujan Constant), only to find out a couple of days later that the question is now different. Because of that, I'll hopefully cover the second challenge in a later post (and will try to provide at least partial answers for both constants associated with the name of Srinivasa Ramanujan).

Perl Toolchain Summit 2019 - CPAN Dependencies Graph

I was grateful to attend for the first time the Perl Toolchain Summit, held this year in Marlow, UK at the Bisham Abbey. I got to meet many of the talented and persistent contributors to the Perl CPAN infrastructure, and also see a country outside North America for the first time. The Perl Toolchain summit is a great event, made possible by the organizers and sponsors, that enables contributors of the Perl CPAN infrastructure to get together and do important work. You can see the results of my project this year at https://cpandeps.grinnz.com (example).

The Project

I decided for my first project, which took the majority of the summit, to work on a replacement for the Stratopan dependency graphs, which have unfortunately gone AWOL. I used these graphs often from MetaCPAN to visualize the dependency impact of a CPAN distribution.

The Perl Toolchain Summit 2019

This year I was again privileged to attend the Perl Toolchain Summit, held at Bisham Abbey, near Marlow in southern England.

The Perl Toolchain summit is an opportunity for the developers and maintainers of Perl's infrastructure to get together and do whatever is necessary to keep that infrastructure running well and improve its services.

I arrived at PTS with a TODO list which I knew was already more than I would be able to complete. But PTS is not just about getting your own work done. A major benefit of having thirty perl hackers together in a room is that often when someone hits a problem or needs guidance or information they can simply wander over to the table where the author of the software they are using is sitting and ask them directly.

Perl::Formance at Perl Toolchain Summit 2019

Finally I could attend the Perl Toolchain Summit again.

As often in the last years I worked on the Benchmark::Perl::Formance toolchain.

The major achievement in this Perl Toolchain Summit was to wrap up the separate major components together under a common umbrella (App::Benchmark::Perl::Formance::Supertool), so it is easier approachable when setting up a new environment or actually running and evaluating benchmarks.

This allows to create a whole overall performance history of Perl5 releases based on a current snapshot of CPAN. Tracking current blead performance is possible as well, though not actively exercised by me right now.

The overall vision can be found on my earlier YAPC::Europe slide decks:

In a couple of days I should have new reliable benchmark results uploaded at

For now, here is a current snapshot with preliminary non-representative results taken with the benchmarks running in "fast mode", i.e., with much smaller datasets or iterations, and slightly disturbed with OS noise:

Perl Weekly Challenge # 5: Anagrams

These are some answers to the Week 5 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Challenge #1: Anagrams of a Word

Write a program which prints out all anagrams for a given word. For more information about Anagram, please check this Wikipedia page.

I'm not sure I fully understand the question, but my understanding is that we are looking for existing words which are anagrams of each other. For example, "pots", "spot", "tops", and "post" are anagrams of each other because they have exactly the same letters rearranged in a different order.

Just as for last week second challenge, I will use a words.txt file containing 113,809 lower-case English words usually accepted for crossword puzzles and other word games. The words.txt file can be found on my Github repository. The original list was contributed to the public domain by Internet activist Grady Ward in the context of the Moby Project. This word list is also mirrored at Project Gutenberg.

Perl Weekly Challenge 005: The Anagrams

When I read the definition of an anagram in Wikipedia, I knew I would need a combinatorics module. I first checked Math::Combinatorics and tried to generate all the anagrams using its next_permutation method. I could have used Algorithm::Combinatorics and its permutations, as well.

But there was a catch: if a letter is repeated in the input word, the anagrams won’t be unique. I didn’t want to reach for List::Util’s uniq as it needs to keep all the anagrams in memory while the iterator had much lower memory footprint. Fortunately, I knew that “unique” means “hash” in Perl.

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use Math::Combinatorics;

my @letters = split //, shift;
my $iter = 'Math::Combinatorics'->new(data  => \@letters);
my %seen;
$seen{$_}++ or say $_ while $_ = join '', $iter->next_permutation;

How to install msys2 and Perl to Windows 7, 8, 10

msys2 is a Linxu-like environment.

mysy2 is available on Windows.

Do you want to use Linux commands and git and Perl on Windows?

msys2 is a good choice.

Most of CPAN module works well.

Mojolicious works well.

Installation of msys2 is easy.

msys2 supports Windows 7, 8, 10, 32bit, 64bit.

I wrote msys2 installation instructions.

msys2 installation to Windows

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