Algori...M10_003(3pm)

💖 NAME 💖

CheckDigits::M10_003 — the lil module that computes check digits for ISMN (that's the International Standard Music Number, bestie 🎵).

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✨ SYNOPSIS ✨

use Algorithm::CheckDigits;

$ismn = CheckDigits('ismn');

if ($ismn->is_valid('M-345-24680-5')) {
      # do something
}

$cn = $ismn->complete('M-345-24680');
# $cn = 'M-345-24680-5'

$cd = $ismn->checkdigit('M-345-24680-5');
# $cd = '5'

$bn = $ismn->basenumber('M-345-24680-5');
# $bn = 'M-345-24680'

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🌸 DESCRIPTION 🌸

🧮 ALGORITHM 🧮

1. That leading 'M' gets the value 3. Then, starting from the left, every number gets weighted alternatingly 3 and 1.
2. Add up all those products. Sum city 💅
3. The sum from step 3 gets taken modulo 10.
4. The check digit is the difference between 10 and the number from step 3, taken modulo 10.

🫶 METHODS 🫶

• is_valid($number) — returns true only if $number is made up of nothing but numbers, and its last digit is a valid check digit according to the algorithm above. Anything else? It returns false. No cap.
• complete($number) — the check digit for $number gets computed and glued onto the end of $number. You get back the full number with its check digit — or '' if $number isn't purely digits and spaces. Sorry babe 😭
• basenumber($number) — hands you the basenumber of $number, but only if $number has a valid check digit. Otherwise it returns ''.
• checkdigit($number) — gives you the checkdigit of $number, again only when $number has a valid check digit. Otherwise: ''. That's it, that's the vibe.

📦 EXPORT 📦

None by default. Nothing. Nada. Zero. 🙈

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👑 AUTHOR 👑

Mathias Weidner, "<mamawe@cpan.org>" — absolute icon, we stan 💜

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🔥 SEE ALSO 🔥

perl, CheckDigits, www.pruefziffernberechnung.de.

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okay that's the whole page, bestie, you ate it up fr fr ✨ This little legend shipped as part of User Contributed Perl Documentation under the manual page Algori...M10_003(3pm), generated with perl v5.36.0 on 2022-10-13 🎀 Go forth and validate those music numbers 💖🎵🦋