R/coalesce_join.R

In yimingli/r-li: Yiming Paul Li's personal R code.

## A useful function from Edward Visel
## https://alistaire.rbind.io/blog/coalescing-joins/
coalesce_join <- function(x, y,
                          by = NULL, suffix = c(".x", ".y"),
                          join = dplyr::full_join, ...) {
    joined <- join(x, y, by = by, suffix = suffix, ...)
    # names of desired output
    cols <- dplyr::union(names(x), names(y))

    to_coalesce <- names(joined)[!names(joined) %in% cols]
    suffix_used <- suffix[ifelse(endsWith(to_coalesce, suffix[1]), 1, 2)]
    # remove suffixes and deduplicate
    to_coalesce <- unique(substr(
        to_coalesce,
        1,
        nchar(to_coalesce) - nchar(suffix_used)
    ))

    coalesced <- purrr::map_dfc(to_coalesce, ~dplyr::coalesce(
        joined[[paste0(.x, suffix[1])]],
        joined[[paste0(.x, suffix[2])]]
    ))
    names(coalesced) <- to_coalesce

    dplyr::bind_cols(joined, coalesced)[cols]
}