top_n() not selecting n

Question

Aim: To plot the first 20 countries in descending order

Problem: When using the top_n function, it insists in selecting all and not just the top 20.

Here is my code:

#Omit missing values
na.omit(kiva_loans)%>%
  #Group by country label
  group_by(country_code)%>%
  dplyr::count(country_code, sort = TRUE)%>%
  top_n(20)%>%
   ggplot(aes(reorder(x=country_code,n),y=n))+
   geom_col(position="dodge",
            color = "black",
            fill="purple")+
   coord_flip()

After the top_n(20) line, the output is:

Which shows that it isn't cutting it off at 20. This is the horrid plot in turn:

it's probably because of the `group_by`, what if you `ungroup()` just before call `top_n`? — RLave, Jul 16 '18 at 09:59
If you want to select top N ordered values you can just use `head(N)` — pogibas, Jul 16 '18 at 10:01

RLave · Accepted Answer · 2020-05-06T09:05:19.703

#Omit missing values
na.omit(kiva_loans)%>%
  #Group by country label
  group_by(country_code)%>%
  dplyr::count(country_code, sort = TRUE)%>%
  ungroup() %>% # add this to ungroup
  top_n(20)%>%
   ggplot(aes(reorder(x=country_code,n),y=n))+
   geom_col(position="dodge",
            color = "black",
            fill="purple")+
   coord_flip()

Just ungroup() before you call top_n

From ?top_n you can read this:

n number of rows to return. If x is grouped, this is the number of rows per group. Will include more than n rows if there are ties.

top_n() not selecting n

1 Answers1