使用 if 比较列值

Question

Here's my df, labeled "Task".

	Country	Confirmed	Ratio
1	Austria	2510071	28.2
2	Bolivia	888175	7.8

I am required to use an if-else statement to do two things: (1) determine which value in the "Ratio" column is greater, and (2) create a new column that says either "Highest" or "Lowest" for the appropriate observation.

I've read dozens of posts about using if-else, but I cannot seem to find examples of a condition that says "see if the 'Ratio' value in this row is greater or lesser than the 'Ratio' value in another row". I've made lots of if() attempts, but they've all failed pretty miserably.

My goal is code that'll produce this output:

	Country	Confirmed	Ratio	Rank
1	Austria	2510071	28.2	Highest
2	Bolivia	888175	7.8	Lowest

Answer 1

If your data frame only has two observations (ie, rows), what you want is fairly straightforward:

# Create some sample data...
df <- data.frame(
  Country = c("Austria", "Boliva"),
  Ratio = c(28.2, 7.8)
)  

# Create a new variable in the data frame...
df$Rank <- ifelse(df$Ratio == max(df$Ratio), "Highest", "Lowest")