The Luhn algorithm — luhn_algo • sweidnumbr

Calculates the control number for a Swedish personal/organisational identity number using the Luhn algorithm.

Usage

luhn_algo(id, multiplier)

Arguments

id: Element with swedish personal identity number.
multiplier: What should each element in id be multiplied with

Value

The control number (last digit in the personal identification number) calculated from id (as integer).

References

Luhn Algorithm.
Skatteverket, Population registration in Sweden. SKV 717B. (2007)
Skatteverket, Personnummer. SKV 704. (2007)

Examples

luhn_algo("121212121212", c(0,0,2,1,2,1,2,1,2,1,2,0))
#> [1] 2
luhn_algo(  "121212121",  c(      2,1,2,1,2,1,2,1,2))
#> [1] 2

## If no multiplier, the default is 
## to find one that match the format of id
luhn_algo("121212121212")
#> 'multiplier' set to: c(0, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2, 0)
#> [1] 2
luhn_algo("12121212121")
#> 'multiplier' set to: c(0, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2)
#> [1] 2
luhn_algo("1212121212")
#> 'multiplier' set to: c(2, 1, 2, 1, 2, 1, 2, 1, 2, 0)
#> [1] 2
luhn_algo("121212121")
#> 'multiplier' set to: c(2, 1, 2, 1, 2, 1, 2, 1, 2)
#> [1] 2

## Also for multiple pin 
## (as long they are all of the same format)
luhn_algo(c("12121212121", "19850504333"))
#> 'multiplier' set to: c(0, 0, 2, 1, 2, 1, 2, 1, 2, 1, 2)
#> [1] 2 4
if (FALSE) {
try(luhn_algo(c("12121212121", "850504333"))) ## Different formats should fail!
}