df %>%
  mutate(trimmed_column = str_trim(column),
        trimmed_column_lower = str_to_lower(trimmed_column))

df1 %>%
  full_join(df2, by = c("column_name_1", "column_name_2"), 
            suffix = c("_df1", "_df2")) 
%>%
  replace_na(list(n_batman = 0, n_star_wars = 0))