4.8 Exercises

  1. Draw the reactive graph for each app.

  2. What happens if you flip fct_infreq() and fct_lump() in the code that reduces the summary tables?

Answer 
injuries %>%
  mutate(diag = fct_infreq(fct_lump(diag)), n = 5) %>%
  group_by(diag) %>%
  summarise(n = as.integer(sum(weight)))
## # A tibble: 7 × 2
##   diag                        n
##   <fct>                   <int>
## 1 Other Or Not Stated   1806436
## 2 Fracture              1558961
## 3 Laceration            1432407
## 4 Strain, Sprain        1432556
## 5 Contusion Or Abrasion 1451987
## 6 Inter Organ Injury     988494
## 7 Other                  940652

This order lumped the rarer conditions into “Other” and then did the sorting. However, since “Other” was the most frequent label, fct_infreq() then put “Other” at the top, which is less desirable.

  1. Add an input control that lets the user decide how many rows to show in the summary tables.
Answer

refer to code in next section

  1. Provide a way to step through every narrative systematically with forward and backward buttons. Advanced: Make the list of narratives “circular” so that advancing forward from the last narrative takes you to the first.