在R Vector中找到16个最大值

Question

Given the R code below , I was wondering how to create two columns such that the 16 largest values of LR and their corresponding xs when "x" is bounded between .4 and .8 be shown? ( a column for x & a column for the corresponding LR )?

n=100
h=60
x=seq(0,1,by=0.02)
LR <- dbeta(x,h+1,n-h+1)/max(dbeta(x,h+1,n-h+1))

I'm trying the following, but can't create the two columns:

head(sort(LR[which(x<=.8 & x>=.4)], decreasing=TRUE), 16)

Answer 1

您可以在您的条件下使用sort对向量LR的子集进行排序：

sort(LR[x <= .8 & x >= .4],decreasing = TRUE)[1:16]

Answer 2

Here is a way using dplyr :

library(dplyr)
df <- data.frame(x, LR)
df1 <- df %>%
  filter((x >= 0.4) & (x <= 0.8)) %>% 
  top_n(16, LR)

# to save the data
write.csv(df1, "abc.csv", row.names=FALSE)