dataframe - How to filter for value in one column based on values from other columns in R?

Question

Here is my dataset:

df <- data.frame(label = c(1,2,3,4,5), measurement = c(100.5, 84.7, 100.7, 77.9, 98.8), size = c(20, 19, 20, 20, 15)) 

Now I want to be able to obtain the label (from label column) that has the maximum size. However, as in the example above, three of the labels have the maximum value of 20. I want my tie breaker to be the measurement values. So in this case, out of the three values of 20 from the size column, measurement of 100.7 is the greatest.

So I would run the code and it would return 3 has the label I should go with. How can I do this across columns?

Answer 1

You can order the dataframe in descending order based on size and measurement column and then extract the first label from it.

df1 <- df[with(df, order(-size, -measurement)), ]
df1$label[1]
#[1] 3

Or sort them in ascending order and extract the last value. Using dplyr :

library(dplyr)

df %>%
  arrange(size, measurement) %>%
  pull(label) %>% last
#[1] 3