R/make_edgelist.R

In judgelord/netlit: Augment a Literature Review with Network Analysis Statistics

make_edgelist <- function(data, edge_attributes = NULL, from = "from", to = "to") {

  if (inherits(data, "netlit_edgelist")) {
    if (is_empty(edge_attributes) && ncol(data) > 2) {
      edge_attributes <- names(data)[-(1:2)]
    }
  }
  else {
    data <- process_from_to_data(data, from, to)
  }

  edgelist <- pare_edgelist(data, edge_attributes)

  graph <- igraph::graph_from_data_frame(edgelist, directed = TRUE)

  edgelist$edge_betweenness <- igraph::edge_betweenness(graph)

  class(edgelist) <- unique(c("netlit_edgelist", class(edgelist)))

  return(edgelist)
}

pare_edgelist <- function(data, edge_attributes = NULL) {

  if (!is_empty(edge_attributes)) {
    if (!is_character(edge_attributes)) {
      abort("'edge_attributes' should be a character vector of names of columns in the supplied dataset.")
    }
    if (!all(edge_attributes %in% names(data))) {
      not_in_data <- setdiff(edge_attributes, names(data))
      abort(paste0("All values supplied to 'edge_attributes' must be names of columns in the supplied dataset.\nValue(s) not in the dataset:\t",
                   paste0(not_in_data, collapse = ", ")))
    }
    data[!names(data) %in% c(attr(data, "from"), attr(data, "to"), edge_attributes)] <- NULL
  }
  else {
    data[!names(data) %in% c(attr(data, "from"), attr(data, "to"))] <- NULL
  }

  return(data)
}