Added new function top_n_mentions()

NAMESPACE

@@ -5,6 +5,7 @@ export(num_tweets_by_timeperiod)
 export(num_tweets_by_username)
 export(num_users_by_timeperiod)
 export(top_n_hashtags)
+export(top_n_mentions)
 importFrom(dplyr,filter)
 importFrom(dplyr,group_by)
 importFrom(dplyr,mutate)

R/top_n_mentions.R

@@ -0,0 +1,55 @@
+#' Plot top n account mentions
+#'
+#' @description Create a ggplot2 bar chart of the number of times the top `n`
+#'   accounts (ties for `n`th position will be included) were mentioned in
+#'   tweets.
+#'
+#' @param sqlite_con [Class SQLiteConnection](https://rsqlite.r-dbi.org/reference/sqliteconnection-class)
+#'   object that is a connection to an SQLite .db file created by the
+#'   [tidy-tweet package](https://github.com/QUT-Digital-Observatory/tidy_tweet).
+#'   The database contains a collection of tweets in relational tables. This can
+#'   be created with [tweetexploR::connect_to_sqlite_db()].
+#'
+#' @param n Number of accounts to be plotted. Note, ties will be included.
+#'
+#' @return ggplot2 plot.
+#'
+#' @importFrom dplyr mutate rename group_by summarise n slice_max
+#'
+#' @importFrom ggplot2 ggplot aes geom_col labs theme
+#'
+#' @importFrom stringr str_to_lower
+#'
+#' @importFrom rlang .data
+#'
+#' @importFrom stats reorder
+#'
+#' @examples
+#' \dontrun{
+#'
+#' top_n_mentions(sqlite_con, n = 10)
+#' my_plot <- top_n_mentions(sqlite_con, 20)
+#'
+#' }
+#'
+#' @export
+
+top_n_mentions <- function(sqlite_con, n) {
+  DBI::dbGetQuery(sqlite_con,
+  "SELECT username, source_id
+  FROM mention
+  WHERE source_type = 'tweet';") %>%
+    mutate(tag = str_to_lower(.data$username)) %>%
+    rename(account = .data$username) %>%
+    group_by(.data$account) %>%
+    summarise(mentions = n()) %>%
+    slice_max(n = n, order_by = .data$mentions, with_ties = TRUE) %>%
+    ggplot(aes(x = reorder(.data$account, .data$mentions), .data$mentions)) +
+    geom_col() +
+    labs(title = paste0("Top ", n, " accounts mentioned in tweets"),
+         y = "Number of tweets") +
+    configure_y_axis() +
+    ggplot2::coord_flip() +
+    configure_ggplot_theme() +
+    theme(axis.title.y = ggplot2::element_blank())
+}

tests/testthat/test-top_n_mentions.R

@@ -0,0 +1,17 @@
+# Connect to sqlite .db file
+sqlite_con <- connect_to_sqlite_db(test_path("fixtures", "auspol-test.db"))
+
+
+test_that("result is a ggplot2 object", {
+  expect_true(ggplot2::is.ggplot(top_n_mentions(sqlite_con, 10)))
+})
+
+
+test_that("ggplot2 plot has expected output", {
+  vdiffr::expect_doppelganger("top_n_mentions_10",
+                              top_n_mentions(sqlite_con, 10))
+})
+
+
+# Disconnect from database
+DBI::dbDisconnect(sqlite_con)