r - 使用 NA 计算列中位数

Question

我正在尝试计算 R 中各个列的中位数，然后用该列中的每个值减去中值。我在这里面临的问题是我的列中有 N/A，我不想删除它们，但只是返回它们而不减去中位数。例如

ID <- c("A","B","C","D","E") 
Point_A <- c(1, NA, 3, NA, 5) 
Point_B <- c(NA, NA, 1, 3, 2)

df <- data.frame(ID,Point_A ,Point_B)

是否可以计算具有 N/A 的列的中位数？我的结果输出是

+----+---------+---------+
| ID | Point_A | Point_B |
+----+---------+---------+
| A  | -2      | NA      |
| B  | NA      | NA      |
| C  | 0       | -1      |
| D  | NA      | 1       |
| E  | 2       | 0       |
+----+---------+---------+

Answer 1

如果我们谈论真实的 NA 值(根据 OP 评论)，可以做到

df[-1] <- lapply(df[-1], function(x) x - median(x, na.rm = TRUE))
df
#   ID Point_A Point_B
# 1  A      -2      NA
# 2  B      NA      NA
# 3  C       0      -1
# 4  D      NA       1
# 5  E       2       0

或者使用matrixStats包

library(matrixStats)
df[-1] <- df[-1] - colMedians(as.matrix(df[-1]), na.rm = TRUE)

<小时/>

当原始df为

df <- structure(list(ID = structure(1:5, .Label = c("A", "B", "C", 
"D", "E"), class = "factor"), Point_A = c(1, NA, 3, NA, 5), Point_B = c(NA, 
NA, 1, 3, 2)), .Names = c("ID", "Point_A", "Point_B"), row.names = c(NA, 
-5L), class = "data.frame")