Set numeric types beforehand

app.R

@@ -28,7 +28,6 @@ server <- function(input, output, session)
 
     imdb %>%
       filter(id == show_id) %>%
-      mutate_at(vars(season, episode, averageRating, numVotes), as.numeric) %>%
       by(.$season, function(x){
            fit <- lm(averageRating ~ episode, data = x)
            x %>%

preprocess.R

@@ -21,6 +21,7 @@ tvseries %>%
   inner_join(ratings, by = c("eptconst" = "tconst")) %>%
   inner_join(tvepisodes, by = c("eptconst" = "tconst")) %>%
   select(-eptconst, episodeTitle = primaryTitle) %>%
+  mutate_at(vars(season, episode, averageRating, numVotes), as.numeric) %>%
   arrange(seriesTitle, season, episode) ->
 final