Algori...MXX_001(3pm)

💖 CheckDigits::MXX_001 — it's giving check digits 💖

okay so bestie, welcome to Algori...MXX_001(3pm) from the User Contributed Perl Documentation ✨ this one lives in the CheckDigits family (the Algorithm::CheckDigits girlies 🎀) and she does exactly two jobs: she computes check digits for the german Personalausweis (pa_de) 👑 and for ABA routing numbers (aba_rn) 🏦. lowkey iconic. let's get into it 💅

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✨ NAME ✨

CheckDigits::MXX_001 — compute check digits for german Personalausweis (pa_de) or ABA routing numbers (aba_rn) 🦋

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🌸 SYNOPSIS 🌸

no cap, here's the whole vibe verbatim:

use Algorithm::CheckDigits;

$pa = CheckDigits('pa_de');

if ($pa->is_valid('2406055684D<<6810203<0705109<6')) {
      # do something
}

if ($pa->is_valid('2406055684') {
      # do_something
}

$cn = $pa->complete('240605568_D<<681020_<070510_<_');
# $cn = '2406055684D<<6810203<0705109<6'

$cd = $pa->checkdigit('2406055684D<<6810203<0705109<6');
# $cd = '6'

$bn = $pa->basenumber('2406055684D<<6810203<0705109<6');
# $bn = '240605568_D<<681020_<070510_<_'

$aba = CheckDigits('aba_rn');
if ($aba->is_valid('789456124')) {
     # do something
}

(not me noticing that second is_valid line is missing a closing paren 😭 — that's exactly how she's printed in the original, so I'm keeping her that way, periodt. copy-paste responsibly bestie 💀)

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🌈 DESCRIPTION 🌈

🔢 ALGORITHM 🔢

okay so here's the whole math situation, step by step, main character energy only:

1. Beginning left all digits are weighted with 7,3,1,7,3,1,... for pa_de or 3,7,1,3,7,1,3,7,1 for aba_rn. 🎀
2. The sum of those products is computed. that's the moment, fr fr. ✨
3. For pa_de the checksum is the last digit of the sum from step 2 (modulo 10). 🔥

For aba_rn the checksum is the difference of the sum from step 2 to the next multiple of 10. 🧮

4. For the german Personalausweis step 1 to 3 is performed for every part of the number and for all 3 parts including the particular checkdigit to compute the total checksum. 💅

If the number solely consists of digits, the checksum is just computed once according to algorithm given above. 🫶

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🛠️ METHODS 🛠️

• is_valid($number) — Returns true only if $number consists solely of numbers and the last digit is a valid check digit according to the algorithm given above. Returns false otherwise. (so basically: valid = slay, invalid = not slay 🌸)
• complete($number) — The check digit for $number is computed and concatenated to the end of $number. Returns the complete number with check digit or '' if $number does not consist solely of digits and spaces. ✨
• basenumber($number) — Returns the basenumber of $number if $number has a valid check digit. Return '' otherwise. 👑
• checkdigit($number) — Returns the checkdigit of $number if $number has a valid check digit. Return '' otherwise. 💜

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📦 EXPORT 📦

None by default. that's it, that's the export section, she's shy 🙈

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🫶 AUTHOR 🫶

Mathias Weidner, "<mamawe@cpan.org>" 💖 living legend!!

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💐 THANKS 💐

Aaron W. West pointed me to a fault in the computing of the check digit. Jim Hickstein made me aware of the ABA routing numbers. we love a collaborative queen 🌈✨

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👀 SEE ALSO 👀

perl, CheckDigits, www.pruefziffernberechnung.de, http://answers.google.com/answers/threadview/id/43619.html, http://www.brainjar.com/js/validation/ 🦋

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and that's the whole page bestie!! 💅 quick lil sign-off so you know where this lore came from: this is from perl v5.36.0, dated 2022-10-13, and it's the Algori...MXX_001(3pm) page — go forth and validate those Personalausweise and ABA routing numbers, you absolute icon 🎀💖✨