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Hey everybody, back this week with a couple really interesting weekly challenge tasks. The first one is extremely simple, like one-liner simple, and the second one is quite complex and nearly 90 lines long.

Challenge #1 - Fun Sort

This was fun, it's in the name. This challenge took me about 5 minutes. Sort the input, split into even and odd arrays and put them together to print out. Pretty self-explanatory.

#!/usr/bin/perl
use strict;
use v5.24;

my (@even, @odd);
$_ % 2 ? push @odd, $_ : push @even, $_ for sort @ARGV;
say @even, @odd;

Challenge #2 - Not Fun Dijkstra

These are some answers to the Week 251, Task 1, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days from now (on January 14, 2024 at 23:59). This blog post provides some solutions to this challenge. Please don’t read on if you intend to complete the challenge on your own.

Task 1: Concatenation Value

You are given an array of integers, @ints.

Write a script to find the concatenation value of the given array.

The concatenation of two numbers is the number formed by concatenating their numerals.

Today, the popular Dark Sky weather API is shutting down. I did a little write-up for non-Perl devs on DEV.to, but I thought I'd post here a couple of potentially useful modules I released to CPAN recently. 

use Weather::WeatherKit;

my $wk = Weather::WeatherKit->new(
    team_id    => $apple_team_id,
    service_id => $weatherkit_service_id,
    key_id     => $key_id,
    key        => $private_key
);

my %report = $wk->get(
    lat      => 51.2,
    lon      => -1.8,
    dataSets => 'currentWeather'
);

Of course, this API is sort of free, as it requires an Apple developer account. If you don't have one and don't want to get one, there are some alternative APIs, but for the purposes of this post I'll stick to 7Timer, via Weather::Astro7Timer. Even simpler, as it does not need authentication:

A couple very very last-minute solutions to the Weekly Challenge #211. I was crammed for time, so I didn't get to these until the last minute.

Challenge #1

For challenge number 1 I had an idea of the method I would use, but since I've been experimenting with it anyway, I asked ChatGPT for its ideas as well. Because of my lack of time, I wanted to get some help with the design process. ChatGPT is amazing at both developing and describing an algorithm in simple terms to make it understandable. I based my solution somewhat off the AI's algorithm, but I did write it entirely by hand. It's pretty simple, it just iterates across the matrix and makes sure everything matches its diagonal neighbor prior to it.

Another thing you might notice this week is that I actually put my solutions into functions, not just a basic script. Anyways, here it is:

Destination: Graph
Date of Latest Release: Feb 12, 2023
Distribution: Graph
Module version: 0.9726
Main Contributors: Jarkko Hietaniemi (JHI)
Current Maintainer: Neil Bowers (NEILB)
License: [perl_5]

Long time ago I claimed in front of a friend I would write a short introduction to graph theory, but I had been not able to figure out where I should start. Neither I would try today. The mathematical objects graphs, or the abstract data structures graphs, are full of interesting behaviors being studied in the discrete math subdiscipline graph theory. The CPAN module Graph is designed to empower Perl programmers doodle with undirected graphs and directed graphs (and also multigraphs and hypergraphs - not going to visit these functionalities here).

These are some answers to the Week 250, Task 2, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Task 1: Alphanumeric String Value

You are given an array of alphanumeric strings.

Write a script to return the maximum value of alphanumeric string in the given array.

The value of alphanumeric string can be defined as

a) The numeric representation of the string in base 10 if it is made up of digits only. b) otherwise the length of the string

Example 1

Consider a simple module like this:

Topics discussed:

• Bug reporting by email: we commit to nothing as an organisation. Some would-be submitters of issues don’t want to use GitHub. They can just send an email to perl5-porters and hope that some helpful soul will copy-paste to GitHub. We encourage the conventional use of GitHub.
• On the topic email bug reports, it’s likely time to deprecate perlbug as a way to send bug reports. It could be updated to point the user to GitHub, and to print perl -V output (etc.) to copy and paste. We should also have a better set of templates for issues on GitHub.
• The segfaults on feature-class and refaliasing won’t be fixed before 5.38, and should just be documented as “known bugs”
• After we discussed renaming RFC to PPC, the general sentiment seemed to be “in favor”, so we’re going to make the rename
• Rik volunteered to release 5.38, we still need a release manager for 5.37.11
• Some discussions about preparing the Perl Toolchain Summit plans (which will host the first ever in-person PSC meeting)

Notice

These are some answers to the Week 250, Task 1, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Task 1: Smallest Index

You are given an array of integers, @ints.

Write a script to find the smallest index i such that i mod 10 == $ints[i] otherwise return -1.

Example 1

Input: @ints = (0, 1, 2)
Output: 0

i=0: 0 mod 10 = 0 == $ints[0].
i=1: 1 mod 10 = 1 == $ints[1].
i=2: 2 mod 10 = 2 == $ints[2].
All indices have i mod 10 == $ints[i], so we return the smallest index 0.

Example 2

First of all, a greeting. I posted an introduction with a notification of intent to take over a module on CPAN, but the maintainer responded to me. I'm Avery, I'm developing SeekMIDI, a small graphical MIDI sequencer. I started it in 2016 and I took a long break from programming entirely, and I've just restarted developing my programming skills again. For starters, I'm working on Perl Weekly Challenges and bug fixes to modules.

Without further ado, here are my solutions to the PWC #208. All solutions are about to be posted, but this could be a spoiler if you're trying to solve it too. I was very pleased this week that I got it down to about 15-25 minutes for each task, so I'm definitely getting more comfortable in Perl again.

First, task 1:

Hi ! Everyone there ! How are you ?

Until recently I runs all of my Perl scripts as well as Perl_CGI scripts by starting the folowing salutation,

#! /usr/bin/perl -w

The script with this beginning runs well at BASH shell at (/home/mkido/bin) LINUX such as Fedora, Ubuntu, Rocky (Alma-derivative). However, almost right now I noticed some of Perl example around has the different first line as below,

#! /usr/bin/env perl

And it doesn't seem to run at HOME BASH shell (/home/mkido/bin) by simple way of executing it by-itself by the command line. Will someone explain me about what is this [env perl] stuff? Thank you so much.

Mitsuru Kido

Porters,

We had an abbreviated PSC call today, largely due to an unexpected delay.

We discussed offering split-up deprecation categories, so you can no warnings 'deprecated::.xyz' and re-affirmed that we want to do this.

We talked about improving the backcompat of strict-vs-version behavior for use vX where X is older than v5.36 and agreed we’d bring that back, but wanted to discuss more about other related changes to the use-vX code.

These are some answers to the Week 249, Task 1, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days from now (on December 31, 2023 at 23:59). This blog post provides some solutions to this challenge. Please don’t read on if you intend to complete the challenge on your own.

Task 1: Equal Pairs

You are given an array of integers with even number of elements.

Write a script to divide the given array into equal pairs such that:

a) Each element belongs to exactly one pair. b) The elements present in a pair are equal.

Example 1

Quoth the fine manual for Template Toolkit:

The DEFAULT directive is similar to SET but only updates variables that are currently undefined or have no "true" value (in the Perl sense).

Nice. Basically, where SET is like the = operator in Perl, DEFAULT is like the ||= operator. Quite useful! If it were, that is. Because the analogy is only superficially true.

Date of Latest Release: Feb 04, 2023
Distribution: Quiq
Module version: 1.207
Main Contributors: Frank Seitz(FSEITZ)
License: The Artistic License
Source: https://github.com/s31tz/Quiq

Quiq is a "Perl class library for rapid development". The modules are "designed according to uniform principles" (translated from German).

Quiq contains 234 (Ooooops!!!) classes at the time this post is being written and their descriptions are mostly written in German.

It contains several text-based document/markup language code writers, namely Quiq::Tag (for XML), Quiq::Html::MODULES, Quiq::MediaWiki::Markup, Quiq::Css, Quiq::LaTex::MODULES; some network functionalities including Quiq::Http::MODULES, Quiq::Ssh and Quiq::Socket ; some tiny tools like Quiq::Color and Quiq::Stopwatch; some system tools like Quiq::Path, Quiq::TempFile and Quiq::Process; some modules for meta-development including Quiq::Hash and Quiq::Object; some modules for general use like Quiq::Converter, Quiq::Math and Quiq::Epoch. ...

How to learn Perl has been an eternal problem for the Perl community. Compared to many other languages that place an emphasis on teaching the basics and using education as a tool for evangelism we've had sporadic efforts along those lines. Given the size of our community and the fact that the best programmers are often in great demand, we have a hard time pumping out the needed docs and examples.

I've been using ChatGPT quite a lot lately and find that although it makes some mistakes it actually churns out pretty decent Perl if given good instructions. For example here's one I did this AM. We just had the dreaded hour shift here in the US and I'm just not up to thinking so I asked Chat GPT:

"write a perl subroutine that accepts two hashrefs and a list. For each item in the item merge the hashrefs by combining the values into an array ref. "

Here's what it pumped out:

These are some answers to the Week 248, Task 2, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days from now (on December 24, 2023, at 23:59). This blog post provides some solutions to this challenge. Please don’t read on if you intend to complete the challenge on your own.

Task 1: Submatrix Sum

You are given a NxM matrix A of integers.

Write a script to construct a (N-1)x(M-1) matrix B having elements that are the sum over the 2x2 submatrices of A,

b[i,k] = a[i,k] + a[i,k+1] + a[i+1,k] + a[i+1,k+1]

Example 1

I'm back this week with PWC #210. Last week I was very busy and spent a long time reviewing other peoples' far more efficient solutions to #208, so I didn't get to doing any solutions for #209. The usual disclaimer about this could contain spoilers, so if you're trying to solve the challenge yourself you may want to skip this post for now. So let's get right into this.

Kill And Win

For this challenge I decided to use some of the tools I learned about in the solutions other people submitted for #208, especially the ways hashes can make the process more efficient. The goal is to find the number in the list where you can delete the most points by deleting the number and its adjacent numbers plus and minus one. You get to count each number however many times it appears in the list.