如何在不重复较短向量的元素的情况下 cbind 或 rbind 不同长度的向量? [英] How to cbind or rbind different lengths vectors without repeating the elements of the shorter vectors?

问题描述

cbind(1:2, 1:10)  
     [,1] [,2]  
  [1,]    1    1  
  [2,]    2    2  
  [3,]    1    3  
  [4,]    2    4  
  [5,]    1    5  
  [6,]    2    6  
  [7,]    1    7  
  [8,]    2    8  
  [9,]    1    9  
 [10,]    2   10  

我想要一个像下面这样的输出

I want an output like below

[,1] [,2]  
[1,] 1 1  
[2,] 2 2  
[3,]   3  
[4,]   4  
[5,]   5  
[6,]   6  
[7,]   7  
[8,]   8  
[9,]   9  
[10,]  10  

推荐答案

诀窍是让所有输入的长度相同.

The trick is to make all your inputs the same length.

x <- 1:2
y <- 1:10
n <- max(length(x), length(y))
length(x) <- n                      
length(y) <- n

如果您希望输出为数组，则 cbind 有效，但您会获得额外的 NA 值来填充矩形.

If you want you output to be an array, then cbind works, but you get additional NA values to pad out the rectangle.

cbind(x, y)
       x  y
 [1,]  1  1
 [2,]  2  2
 [3,] NA  3
 [4,] NA  4
 [5,] NA  5
 [6,] NA  6
 [7,] NA  7
 [8,] NA  8
 [9,] NA  9
[10,] NA 10

要去掉 NA，输出必须是一个列表.

To get rid of the NAs, the output must be a list.

Map(function(...) 
   {
      ans <- c(...)
      ans[!is.na(ans)]
   }, as.list(x), as.list(y)
)
[[1]]
[1] 1 1

[[2]]
[1] 2 2

[[3]]
[1] 3

[[4]]
[1] 4

[[5]]
[1] 5

[[6]]
[1] 6

[[7]]
[1] 7

[[8]]
[1] 8

[[9]]
[1] 9

[[10]]
[1] 10

我将 mapply(..., SIMPLIFY = FALSE) 换成了 Map.

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