funs.R

# From 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 <- 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]
}


# Convenience functions for counting the number of points in a tract + mutating, and calculating distance to closest point
tractcount <- function(j,k) {
  sapply(st_geometry(j), function(x) suppressMessages(st_within(k,x,sparse = FALSE)) %>% sum)
}

tractdist <- function(j,k) {
  st_distance(st_geometry(j),k) %>% apply(.,1,min)
}