Prepare UCDP data for peacesciencer workflows — ucdp_to

ucdp_to_peacesciencer() standardizes state-year or dyad-year keys to the names expected by peacesciencer and declares the corresponding package attributes. It does not aggregate event data automatically; use ucdp_aggregate() first when observations are not already unique at the requested unit.

Usage

ucdp_to_peacesciencer(
  data,
  type = c("state-year", "dyad-year"),
  system = c("gw", "cow"),
  code = NULL,
  code2 = NULL,
  year = "year",
  from = system,
  crosswalk = NULL,
  check_unique = TRUE
)

Arguments

data: A state-year or dyad-year data frame.
type: "state-year" or "dyad-year".
system: Target state system: "gw" or "cow".
code, code2: Source code columns. code2 is required for dyad-years.
year: Year column.
from: Coding system of the supplied codes. Defaults to system. If it differs, codes are converted with ucdp_country_crosswalk().
crosswalk: Optional frozen crosswalk passed to ucdp_country_crosswalk().
check_unique: Require one row per state-year or dyad-year key?

Value

A data frame with year and gwcode/ccode keys (or numbered dyadic variants) and peacesciencer attributes.

Examples

x <- data.frame(country_id = c(2, 20), year = 2020, events = c(1, 3))
if (requireNamespace("peacesciencer", quietly = TRUE)) {
  ps <- ucdp_to_peacesciencer(x, code = "country_id")
}