如何在两个向量之间取成对并行最大值? [英] How can I take pairwise parallel maximum between two vectors?

问题描述

假设我在 R 中有两个向量，定义如下.

Suppose I have two vectors in R, defined as follows.

a = c(3,3,5)
b = c(2,4,6)

是否有一个函数可以给我 a 的元素和 b 的元素之间的成对最大值，它可以在公式中运行?

Is there a function that will give me the pairwise maximum between the elements of a and the elements of b, which can be run inside a formula?

我尝试这样做，max(a, b) 但它没有得到想要的输出.

I tried to do, max(a, b) but it does not get the desired output.

期望的输出:

C(3,4,6)

实际输出:

6

推荐答案

Pairwise maximum, pmax(a, b), will give c(3,4,6).

Pairwise maximum, pmax(a, b), will give c(3,4,6).

a <- c(3,3,5,NA,1)
b <- c(2,4,6,0,NA)

pmax(a, b)
# [1]  3  4  6 NA NA

pmax(a, b, na.rm = TRUE)
# [1] 3 4 6 0 1

还有一个成对最小值

pmin(a, b)
# [1]  2  3  5 NA NA

pmin(a, b, na.rm = TRUE)
# [1] 2 3 5 0 1

还有一个成对和，我从 这个问题/答案 有时对我非常有用:

And a pairwise sum, which I pulled from this question/answer has been very useful to me at times:

psum(a, b) # == a + b
# [1]  5  7 11 NA NA

psum(a, b, na.rm = TRUE)
# [1]  5  7 11  0  1

psum(c(-1, NA, 4), c(0, NA, NA))
# [1] -1 NA NA

psum(c(-1, NA, 4), c(0, NA, NA), na.rm = TRUE)
# [1] -1 NA  4

psum <- function(..., na.rm = FALSE) {
  dat <- do.call(cbind, list(...))
  res <- rowSums(dat, na.rm = na.rm) 
  idx_na <- !rowSums(!is.na(dat))
  res[idx_na] <- NA
  res 
}

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