blogs.perl.org

These are some answers to the Week 125 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Task 1: Pythagorean Triples

You are given a positive integer $N.

Write a script to print all Pythagorean Triples containing $N as a member. Print -1 if it can’t be a member of any.

Triples with the same set of elements are considered the same, i.e. if your script has already printed (3, 4, 5), (4, 3, 5) should not be printed.

The famous Pythagorean theorem states that in a right angle triangle, the length of the two shorter sides and the length of the longest side are related by a²+b² = c².

A Pythagorean triple refers to the triple of three integers whose lengths can compose a right-angled triangle.

Example:

So I like to keep local copies of my blogs.perl.org blog posts as Atom entries, but noticed yesterday that I had a few gaps in my collection. The Atom feeds offered by blogs.perl.org only have the most recent articles though, so I decided to write a quick script to scrape the posts. Luckily, I managed to get a table containing the URLs for each post I needed, so I didn't need to bother with following links to find the pages; I just needed to grab the content from them.

I thought some people might find the code interesting especially for its use of lazy attributes. This is one of those "it only needs to be used once, so making the code maintainable isn't important" kinds of projects, do bear that in mind. I've cleaned up the whitespace and added comments for this blog post, but other than that, it's just a quickly hacked together script.

hi, as already indicated in that reddit post, a new bot contest was planned for next fall: it has now a planned starting date.

it would be nice to see more than ten perl lovers to join the fun, which will also permit to be seen in the loop back stats, unlike the previous contest.

• the community developed an extension to write code locally.
• the community can write contests from easy to expert: see Bender 1, 2, 3, against 4 ; or Pikaptcha 1, 2, 3, 4.
• the admins will accept to upgrade to perl 7 when time has come, but, i guess, the level of priority will depend on the number of people asking for it.

As a programmer whose first job was in the mortgage software industry, “TIL” has always meant “Truth In Lending” to me: you know, that document that the bank is required to give you when you get a mortgage, that’s supposed to explain how much you’re really paying after all the bank’s hidden finance charges, except the numbers don’t seem to make any sense so you just sign it anyway and don’t know anything more than you did before?  Yeah, that one.

Of course, nowadays it means something else, and I’ve had to redirect my ossified mental patterns into new channels, so that, now when I see “TIL,” I can have my brain recognize it as “Today I Learned.” Which is a handy phrase: it encapsulates feelings of discovery, serendipity, and epiphany all into one.  And TIL¹ that the way I’ve always tried to write code has a name, a history, and a venerable progenitor—most of my life, without even realizing it, I’ve been trying to use literate programming (only without the tangling).

These are some answers to the Week 123 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due on August 1, 2021 at 24:00. This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Ugly Numbers

You are given an integer $n >= 1.

Write a script to find the $nth element of Ugly Numbers.

Ugly numbers are those number whose prime factors are 2, 3 or 5. For example, the first 10 Ugly Numbers are 1, 2, 3, 4, 5, 6, 8, 9, 10, 12.

Example

Input: $n = 7
Output: 8

Input: $n = 10
Output: 12

Ugly Numbers in Raku

Please follow the blog where I discuss the "Prime Sum" task of "The Weekly Challenge - 076".

https://perlweeklychallenge.org/blog/weekly-challenge-076

If you want to challenge yourself on programming, especially on Perl and/or Raku, go to https://perlweeklychallenge.org, code the latest challenges, submit codes on-time (by GitHub or email).

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Task 1 Prime Sum

What a dish for math geeks! Goldbach's conjecture is immediately recalled. I have chosen to print the answer first, than give the expression and explanation.

I was working on the completely fresh rewrite of perlmodules.net, when I decided I want to use WebSockets with this site.

So "innovations" started flowing through my mind in order to achieve WebSocketry, and ended-up deciding it would be very helpful if I could use ReactiveX on my Mojolicious site, in terms of size and neatness of the code, buglessness and maintainability.

This is how we ended up with RxPerl, a project I spent a lot of time to make it work well.

Now at version v0.16.0 on CPAN, it is a release candidate. I would like to ask anyone interested to take a look and see if they can find things they don't like about it, in advance of its proper v6.0.0 release which could happen late next week.

https://metacpan.org/pod/RxPerl

Thanks.

These are some answers to the Week 122 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days, on July 25, 2021 at 24:00. This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Average of Stream

You are given a stream of numbers, @N.

Write a script to print the average of the stream at every point.

Example:

Input: @N = (10, 20, 30, 40, 50, 60, 70, 80, 90, ...)
Output:      10, 15, 20, 25, 30, 35, 40, 45, 50, ...

Average of first number is 10.
Average of first 2 numbers (10+20)/2 = 15
Average of first 3 numbers (10+20+30)/3 = 20
Average of first 4 numbers (10+20+30+40)/4 = 25 and so on.

Today we will focus on a simple task: listing the files contained in a directory, sort them by modification time (see mtime and display the result in a JSON array.

We are gonna use Mojo::File for the file system part and Mojolicious::Lite to expose those data on a simple but effective JSON API.

Time for another monthly report? Time just flies.

It was the most busiest month of the year 2020 for me. Of course, most of my spare time was dedicated to The Weekly Challenge. We, as a team, created record of 100+ contributions 4 weeks in a row. It was hectic and exhausting, I must admit.

With every passing week, the team is also growing. Team members are blogging more often. As of today, we have received 3000+ Perl contributions and 2000+ Raku contributions. For blogs, very soon we would cross 1000 mark, currently it stands at 940. Did I expect such response in the beginning? No, never dream of such support.

Encouraged by Gabor Szabo, I created my Patreon profile for the first time. I am overwhelmed by the support I have received so far. I would like to take this opportunitity to thank each and every supporters.

A little over a month ago I learned about the Perl Weekly Challenges. The site states the challenges are for any skill level. So, I went and took a look. After looking at the first challenge that week, I realized “any skill level” did not mean my skill level.

My skill level is pretty basic.

I can …

• open, read, and close text files and do simple manipulation of the data.
• add, subtract, multiply, and divide when it comes to math.
• tack on words or phrases to the beginnings or ends of strings okay with loops.
• write some basic regexen.
• even roll things randomly.
• do most of the above conditionally.

… that is about it.

I read the challenges and my mind is totally blank on where to start after…

I wish I could grasp the concepts in the Perl Weekly Challenges, especially the math. I have not taken a math class in over 30 years, and what math I remember is, as I said, pretty basic.

Oh, and one needs to be more than a little familiar with Git and GitHub to contribute, which I am not.

These are some answers to the Week 121 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due on July 18, 2021 at 24:00. This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

You are given integers 0 <= $m <= 255 and 1 <= $n <= 8.

Write a script to invert $n bit from the end of the binary representation of $m and print the decimal representation of the new binary number.

Example:

If you want to challenge yourself on programming, especially on Perl and/or Raku, go to https://perlweeklychallenge.org, code the latest challenges, submit codes on-time (by GitHub or email).

Continued from the discussion of Task 1.

Task 2 Largest Rectangle Histogram

I am not a narcissist; though some of my actions are narcissistic traits, it does not imply that there is yet another narcissist; I am motivating myself for a better self.

Back to the task. This look like a task testing our overall commanding of the language (especially when the bonus is also considered), not an algorithm-oriented task.

At the first sight, looking for the largest rectangle seems uneasy. My order of coding has been: Perl code, Python code, Java code (3 at a time because I got a day-off on Tuesday) and (after a few days) Lisp code. The following is my note during coding the Perl of the task, informally:

Please follow the blog where I discuss the two tasks "Coins Sum" and "Largest Rectangle Histogram" of "The Weekly Challenge - 075".

https://perlweeklychallenge.org/blog/weekly-challenge-075

Prompted by a recent question on PerlMonks, I've been thinking a bit recently on marshalling and unmarshalling Perl objects. If you're happy using Data::Dumper's format, then it's trivial, but today we're looking at JSON.

If you just want to encode your objects as JSON, that's very easy. Just add a TO_JSON method to all your classes. This can be done in a role to eliminate duplication, and in most cases can be as simple as:

The difficulty comes in going the other direction.

These are some answers to the Week 120 of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a couple of days, on July 11, 2021). This blog post offers some solutions to this challenge, please don’t read on if you intend to complete the challenge on your own.

Task 1: Swap Odd/Even Bits

You are given a positive integer $N less than or equal to 255.

Write a script to swap the odd positioned bit with even positioned bit and print the decimal equivalent of the new binary representation.

Example:

If you want to challenge yourself on programming, especially on Perl and/or Raku, go to https://perlweeklychallenge.org, code the latest challenges, submit codes on-time (by GitHub or email).

Thanks for the volunteers, there are code Reviews on Perl/Raku; in addition, on each Monday, you can read the RECAP linking others' solutions and blogs; I often learn something from both RECAP and Perl Review.

Do tell me, if I am wrong or you strongly oppose my statements!

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While the weekly challenge is fighting towards new record of number of submissions, I am starting my own programming adventure. Congratulations to CY Fung, she knows how to code in Python and Java now. I am going to submit guest solutions in these two languages for the coming challenges.

Task 1 Coins Sum

You can see the results here.

The following is my reflection on those results and doesn't reflect anyone else's opinions. They may not even really be my opinions.

Who responded?

Some 85.9% respondents self identify as Perl programmers and 22.7% as Raku programmers, 33.2% as Software project leaders, and 30% as Business Owners.

Brand Values

In regards to brand values there is a huge gap between perception and expectation. I've cut off the long tail of "Other" responses for clarity, follow the link at the top to see them.

(The long titles overlap. The first 5 are Amateur, Passionate about helping software projects, Powered by Volunteers, Professional, Secretive)

(The long titles overlap. The first 5 are Passionate..., Powered by Volunteers, Professional, Servant Leadership, Supportive)

https://perlweeklychallenge.org/blog/weekly-challenge-074