Algori...M10_001(3pm)

💖 CheckDigits::M10_001 — the check digit bestie 💖

okay so this is a page from the User Contributed Perl Documentation for Algori...M10_001(3pm) — yes the title got truncated, she's mysterious like that 🎀 — and she's here to compute check digits for a whole squad of things.

✨ NAME ✨

CheckDigits::M10_001 — compute check digits for Bahncard (DE), IMEI, IMEISV, ISIN, Miles&More, Payback (DE), Personnummer (SE), Passport (BR), Credit Cards, SSN (US), Samordningsnummer (SE), VAT RN (ES), VAT RN (IT), VAT RN (SE), International Securities Identifikation Number (ISIN), CUSIP

like. that's a lot of letters and numbers bestie, but she handles ALL of them 💅

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🌸 SYNOPSIS 🌸

watch her work:

use Algorithm::CheckDigits;

$visa = CheckDigits('visa');

if ($visa->is_valid('4111 1111 1111 1111')) {
      # do something
}

$cn = $visa->complete('4111 1111 1111 111');
# $cn = '4111 1111 1111 1111'

$cd = $visa->checkdigit('4111 1111 1111 1111');
# $cd = '7'

$bn = $visa->basenumber('4111 1111 1111 1111');
# $bn = '4111 1111 1111 111'

not her doing the visa thing effortlessly in four lines 😭 iconic behaviour fr fr

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🦋 DESCRIPTION 🦋

💫 ALGORITHM 💫

okay so the math is literally this, in order:

1. Beginning right, all numbers are weighted alternatively 1 and 2 (that is, the check digit is weighted 1). no cap.
2. The total of the digits of all products is computed. slay.
3. The sum of step 3 ist taken modulo 10. (yes she said step 3, she's a little chaotic, we love her)
4. The check digit is the difference between 10 and the number from step 3. periodt.

to validate: the total of the digits of all numbers inclusive the check digit, taken modulo 10, must be 0. that's the vibe check 🧚

🫶 METHODS 🫶

• is_valid($number) — Returns true only if the last digit is a valid check digit according to the algorithm given above. Returns false otherwise.

heads up bestie: if the checked number is of type CUSIP, the number must be exact 9 digits or letters long and must not have spaces in between. no sneaky spaces. not one. 🙈

• 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.

🌈 EXPORT 🌈

None by default. she's not clingy, she gives nothing away unless you ask 💜

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👑 AUTHOR 👑

Mathias Weidner, "<mamawe@cpan.org>" — the icon who built her 🎀

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⭐ SEE ALSO ⭐

• perl
• Algorithm::CheckDigits
• www.pruefziffernberechnung.de.
• http://en.wikipedia.org/wiki/CUSIP

For IMEI, IMEISV: ETSI Technical Specification TS 100 508 (v6.2.0)

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and that's the whole page bestie 🌸 this one's running on perl v5.36.0, dated 2022-10-13 — she's from the User Contributed Perl Documentation and she's been serving check digits ever since. mwah 💅💖✨