计算数据框中多列的中位数

Question

我想计算下面我的 df 数据库的中位数。在这种情况下，我想获得 A1 到 A10 列的中位数结果，并 return 分别获得这些列的结果。

谢谢！

#database
df <- structure(
 list(D1 = c("a","a","b","b","b"), 
      D2 = c("c","d","c","d","c"), D3 = c("X","X","Y","Z","Z"), A1=c(1,2,3,4,5),A2=c(4,2,3,4,4), A3=c(1,2,3,4,6),
      A4=c(1,9,4,4,6),A5=c(1,4,3,9,6),A6=c(1,2,4,4,8),A7=c(1,1,3,4,7),A8=c(1,6,4,4,2),A9=c(1,2,3,4,6),A10=c(1,5,3,2,7)),
      class = "data.frame", row.names = c(NA, -5L))

Answer 1

我们可以遍历 numeric 列并得到 median

library(dplyr)
df %>% 
   summarise(across(where(is.numeric), median))
  A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
1  3  4  3  4  4  4  3  4  3   3

或使用 matrixStats

中的 colMedians

library(matrixStats)
colMedians(as.matrix(df[startsWith(names(df), "A")]))
 [1] 3 4 3 4 4 4 3 4 3 3

或在base R

sapply(df[startsWith(names(df), "A")], median)
 A1  A2  A3  A4  A5  A6  A7  A8  A9 A10 
  3   4   3   4   4   4   3   4   3   3

Answer 2

如果您想保持简单：

apply(df[, 4:13], 2, median)
 A1  A2  A3  A4  A5  A6  A7  A8  A9 A10 
  3   4   3   4   4   4   3   4   3   3

计算数据框中多列的中位数

Calculate medians of multiple columns in a data frame

r

median