https://perlmaven.com/compare-the-speed-of-perl-and-python-regex

Oof. I know this is a pretty old post, but also very misleading. It says 20 times speed difference between Python and Perl, but it just uses regexp in Python in very inefficient way, and what is measures is actually not regexp speed, but other aspects of the language.

First: If you use c = re.compile(r'y') before you even a start of the loop, and then c.search(line), difference shrinks to 2 times. (Perl does it implicitly to some extent because it compiles regular expression at perl source code parsing time, something that JavaScript for example often does, but cannot be done with Python out of the box).

Second: If you actually first do a proper control test, and test just looping with a function does only return false, instead of calling regexp engine at all, you will see that the time difference as well as absolute different is still similar. Which means you are not testing regexp speed, but other things in the interpreter and language.

The article conclusion:

The regex engine in Perl is much faster than the regex engine of Python.

is simply false. It is faster, and easier to use, but not astronomically faster, and highly depends on regexp.

Sure, perl has easier to use and usually faster regexp, but the tests in the article are just done in a very lazy way. It took me more time to write this "comment" on github, than run proper tests.

https://perlmaven.com/sending-tweets-from-a-perl-script

https://perlmaven.com/static-and-state-variables-in-perl

This line, 'Thus $count is effectively a static variable.'. Should it be:
Thus $counter is effectively a static variable.

Thank you for your work! Only links 1-4 are available on the page OOP - Object Oriented Perl. Are the other links broken or to be finished?

https://perlmaven.com/convert-markdown-to-html

Try Text::Markdown::Discount or Markdown::Render. The latter will use the GitHub API which supports two different modes (gfm, markdown).

https://perlmaven.com/indexing-emails-in-an-mbox

No biggie. Just noticed an extra final closing brace in the first listing in this article.

I would love to learn more. I need to read more of your articles. I'm not sure what is the advantage of using main::cnt instead of just declaring a global "my cnt;" somewhere early on. I'll try to read & learn more from your articles.

Peace -- Marnix

hello, I'm not very good at this. I can get the keys and values from a regular hash and write them as a .csv file to disk.
I can get the values from individual keys in an array of hashes, which your excellent web site showed how to make.
$L_vars[0]={
image_file=>"my_images",
start_frame=>30,
end_frame=>50
}
but I'm having problems getting the keys, values from that as can't find the syntax to address the hash.
help appreciated.
regards
mick

On https://perlmaven.com/out-of-memory

• Does Linux print "Out of memory"?
• Does perl print "Out of memory"?

Couldn't the thing saying those words identify itself?

https://perlmaven.com/counter-dancer2-redis-docker

docker-compose up gives me:

% docker-compose up
no configuration file provided: not found

Apparently, I need a docker-compose.yml at this point.

I love it! However this code will end long before the computer system runs out of memory - since the Fibonacci numbers grow exponentially (as φ^n), this will exceed the maximum integer storage very quickly.

If we take the maximum integer value of 2^64, this will be exceeded by the 93rd Fibonacci number. If we're looking for accuracy of resolution (which is lost around 2^53, the value will no longer be accurate after the 80th Fibonacci number.

P.S. This is my first GitHub post; please let me know if I'm doing this wrong.

https://github.com/szabgab/perlmaven.com/blob/fb2c8d96b79ba13c0c73041d39564023cfa92d83/sites/ru/pages/otkrytie-i-chtenie-faylov.txt

Hi Gabor!
I found mistype in
http://ru.perlmaven.com/otkrytie-i-chtenie-faylov
but I cannot edit it, when I fork https://github.com/szabgab/perlmaven.com
these page is not available

Deal Perl Maven,

How could I create an email with multiple attachments?

I need my Perl script to email out PDF's and Email files to various distribution lists.

Thanks

Probably here is translation issue. The string cat is not started at symbol 10, It started at symbol 11. Probably you mean started at **index** 10

file in this repository: sites/en/pages/perl-based-open-source-products.txt

under "Mailing list", the link to Minimalist points to a domain parking site.
On archive.org, the latest "working" version is from June 2014. There seems to exist a fork on github madroach/minimalist with latest commit in November 2014.

Since it is no longer maintained (the page on archive.org explicitly says so), Unless someone resurrects it, I think it should be removed from this list...

About http://perlmaven.com/web-sites-powered-by-perl-with-open-source-code-base, the source of PAUSE is also on Github.

https://perlmaven.com/use-of-uninitialized-value

In this use case, $x becomes undef. I doubt it matters why, but as an example, reading an expected numerical value from an external database can cause it if the code return is empty.
Then a choice has to be made : create another database with not-null values, or assign a value of '0' (zero) in Perl, thus :
< if ($x[$k] eq '') {$x[$k] = 0}>
where $k is a variable that sets an index to the array @x.

When the code is run, a warning is returned for each undefined value.
This isn't necessarily a problem, as the warnings can be ignored, but I would prefer to be able to set a flag to temporarily prevent the warning message being thrown.

The most important use of T::RL::G, in my opinion, is to make perl -d useable.

some people thing -> some people think
See line 13 of source.

https://perlmaven.com/plack-app-cgibin

Installing https://metacpan.org/pod/CGI::Emulate::PSGI wasn't mentioned.

It's needed in order to run CGI with Plack.

It's also mentioned here:

https://metacpan.org/pod/Plack::App::CGIBin

In addition, I also had to install CGI-Compile to make it work.

https://metacpan.org/pod/CGI::Compile

https://perlmaven.com/static-and-state-variables-in-perl

Something to watch out for is the use of a static variable in a loop construct.

Eg:

{
	my $stated=0;

	sub counter
	{
		for $stated (1..5) {
			print "$stated\n";
			&resetcount if ($stated>3);
		}
	}

	sub resetcount
	{
		$stated=0;
	}
}

counter();

In this example the call to resetcount when $stated>3 does not effect the value of the loop or the $stated in loop. Consequently, the loop iterates 5 times quite happily. This also applies in a while loop, where the while test will not test a change of value executed in a sub that is called outside the scope of the while.

https://perlmaven.com/variable-will-not-stay-shared

Just a typo: "When using fork non of the variables will remain shared."

Should be "none of ...", I think.

Enjoy your columns.

I don't know if it supports tables, though: https://metacpan.org/dist/CommonMark/view/lib/CommonMark.pod

https://perlmaven.com/convert-markdown-to-html

Thanks for blog post https://perlmaven.com/install-developer-dependencies-first-test-css

After applying your pull request to https://metacpan.org/dist/Date-ManipX-Almanac I decided to dive into the the file to try to bend it to my own biases. The most significant change so far was to try to run multiple versions of Perl -- the latest available, and the oldest the distro supports (or the oldest available, if they're different). The distro your pull request was against was written to Perl 5.10, which caused no problem. The next one I tried was written to Perl 5.6.2 and produced exactly the error you describe under darwin and ubuntu (Windows uses Strawberry and does not go back before 5.14). Lacking a way to troubleshoot, I simply pretended Perl 5.6.2 was not available on that platform and used 5.8.

Now I have a way to dig under the hood and find out what is really going on. Thanks again.

https://ru.perlmaven.com/kavychki-interpolyaciya-i-ekranirovanie-strok-v-perl

Thank you for your awesome Perl website!
I noticed that there was a missing semi-colon for this example:
https://github.com/szabgab/perlmaven.com/blob/15c9857ac77fc0ed7efe62aae096ebbc572e89bf/sites/en/pages/trim.txt#LL48C23-L48C23

Cheers!

Thanks for your article on reading Excel from perl! But there is a serious error, regarding rows and columns, that is causing much confusion among readers. You wrote: "The next snippet will read the first row of the first sheet (which is usually represented by the letter A)". But spreadsheets do not use letters to represent rows. The COLUMNS are represented as letters, and the rows are represented as NUMBERS. Consequently, the output is incorrectly labeled in the snippet of code that you show for displaying the content of a row. The corrected code should be:

    my @row = Spreadsheet::Read::row($book->[1], 1);
    for my $i (0 .. $#row) {
        say chr(ord('A')+$i) . '1 ' . ($row[$i] // '');
    }

And the output is similarly incorrectly labeled in the snippet of code for fetching all the rows. That corrected code should be:

    my @rows = Spreadsheet::Read::rows($book->[1]);
    foreach my $i (1 .. scalar @rows) {
        foreach my $j (1 .. scalar @{$rows[$i-1]}) {
            say chr(ord('A')+$j-1) . " $i " . ($rows[$i-1][$j-1] // '');
        }

Would you be willing to make these corrections in your article?

On should be One

Hi Gregor,

installation of cpanm is also possible via

cpan App::cpanminus


Thanks for your activities around Perl.

BR

https://es.perlmaven.com/ayuda

Please, I need your help. I had been created the string: $averages
$averages="get_averages(%HoH, '2023-01-01','2023-01-02','2023-01-03',)";

#The string above has been created for call a function to calculate averages for the days the user know averages. (get_averages)

The variable $averages is a string variable, BUT it must a call the function get_averages with the parameters that the user had been selected.

Please, will you help guide me how to call the function get_averages.

Regards
Xochitl

https://perlmaven.com/factorial-in-perl

Factorial of zero is not calculated properly by List::Util qw(reduce), hence I suggest this tiny modification.

$v == 0 ? 1 : reduce { $a * $b } 1 .. $v;

dead link to Test automation book:
is: http://de.perlmaven.com/test-automation-using-perl-e-book

should be: http://perlmaven.com/test-automation-using-perl-e-book

https://perlmaven.com/bitbucket-pipelines-testing-perl-projects

https://perlmaven.com/segmentation-fault-core-dumped-while-connecting-to-oracle

Hello, this solved my issue for AIX 7.1 with ORacle 11.2.0.4

All I had to do was change the date.

Maybe it's too obvious to include, but my first response to a 500 error is:

perl -cw app.pl

Most of my scripts use $ENV{DOCUMENT_ROOT} or other environment variables, so this works better:

export DOCUMENT_ROOT=/path/to/website/root
perl -cw app.pl

I think there is a way to persist and reload an SQLite DB. Maybe put the persist commands in an END block and the reload in a BEGIN block.

https://perlmaven.com/setup-github-actions

Hi,

I tried your suggested setup for a Dist::Zilla distribution on my own repo (https://github.com/sbakker/perl-Term-CLI). For some reason I needed to add a cpanm --notest Dist::Zilla because I was getting dzil: command not found errors.

I now get it to run the tests, but I'm getting failures which do not appear when I pull the Docker image on my laptop and run the tests in there myself. The released module on CPAN also does not show errors in the test results.

I'm guessing that, since this module uses builds on Term::ReadLine and Term::ReadLine::Gnu specifically, the Docker image on Github runs the tests in some bizarre (pseudo-)terminal setup (I'm getting errors from deep within Term::ReadKey).

Any hints on how to debug this would be more than welcome.

Cheers,
Steven