calculate_check_digit: Calculate Check Digit Using DIN/ISO 7064, Mod 11,10

In DIZtools: Lightweight Utilities for 'DIZ' R Package Development

Calculate Check Digit Using DIN/ISO 7064, Mod 11,10

Description

This function calculates the check digit for a given ID based on the DIN ISO 7064, Mod 11,10 algorithm.

Usage

calculate_check_digit(patid)

Arguments

patid

A numeric or character string representing the ID. It should be either 9 or 10 digits long.

Details

The function processes the input 'patid' as follows: - If the input has 10 digits and does not start with '0', it is assumed to be a patient ID with a check digit. The check digit is removed. - If the input has 9 digits, a leading '0' is added. - If the input has 10 digits and starts with '0', it is already in the expected format. - If the input does not match these cases, an error message is returned.

The check digit is calculated using the ISO 7064, Mod 11,10 method.

Value

An integer representing the computed check digit (0-9). Returns 'NA' if the input is invalid.

Examples

calculate_check_digit("100000138")  # Returns check digit (1) for this ID
calculate_check_digit(123456789)    # Works with numeric input as well (6)

DIZtools documentation built on Nov. 6, 2025, 1:10 a.m.