libbib (version 1.6.4)

get_isbn_10_check_digit: Get ISBN 10 check digit

Description

Takes a string representation of an ISBN 10 and returns the check digit that satisfies the necessary condition. It can take a 10 digit string (and ignore the already extant check digit) or a 9 digit string (without the last digit)

Usage

get_isbn_10_check_digit(x, allow.hyphens = FALSE, errors.as.nas = FALSE)

Value

Returns the character check digit that satifies the mod 11 condition. Returns "X" if 10. Returns NA if input is NA

Arguments

x

A string of 9 or 10 digits

allow.hyphens

A logical indicating whether the hyphen separator should be allowed (default is FALSE)

errors.as.nas

return NA if error instead of throwing error (default is FALSE)

Examples

get_isbn_10_check_digit("012491540X")
get_isbn_10_check_digit("0-124-91540-X", allow.hyphens=TRUE)

# nine digit string
get_isbn_10_check_digit("900403781")

get_isbn_10_check_digit("onetwothre", errors.as.nas=TRUE)  # NA

# vectorized
get_isbn_10_check_digit(c("012491540X", "9004037810", "900403781"))