Extract Year from a GEDCOM Date String

Extracts a four-digit year from a GEDCOM date string, stripping calendar escapes (e.g., `\@#DGREGORIAN\@`) and common qualifiers (`ABT`, `BEF`, `AFT`, `BET`/`AND`) before searching for the year. Returns `NA_integer_` when no year is found. The function can be used to extract years from various GEDCOM date formats, including approximate dates and date ranges.

Usage

extractGedcomYear(x, year_len = 4)

Arguments

x

Character vector of GEDCOM date strings.

year_len

Integer specifying the length of the year to extract (default is 4).

Value

Integer vector of years.

Examples

extractGedcomYear(c("ABT 1 JAN 1900", "BEF 31 DEC 2000", "1850", NA))
#> [1] 1900 2000 1850   NA