สร้างกราฟสำหรับผู้ใช้ประเภทต่าง ๆ

subscribers <- bike_dat %>% 
  # Filter for rows where usertype is Subscriber
  ___(___ == "___")

# Count the number of subscriber trips
n_subscriber_trips <- nrow(___)

subscriber_trip_graph <- subscribers %>% 
  # Group by from_station_id and to_station_id
  ___(___, ___) %>% 
  # Calculate summary statistics
  summarize(
    # Set weights as proportion of total trips
    weights = ___() / n_subscriber_trips
  ) %>%
  # Make a graph from the data frame
  graph_from_dataframe()