R:保留1行/列矩阵

Question

给定一行,一列或一个单元格的矩阵,我需要在保持矩阵结构的同时重新排序行.我尝试添加,drop=F但它不起作用!我做了什么？

test = matrix(letters[1:5]) # is a matrix
test[5:1,,drop=F]           # not a matrix

test2 = matrix(letters[1:5],nrow=1) # is a matrix
test2[1:1,,drop=F]                  # not a matrix

test3 = matrix(1)  # is a matrix
test3[1:1,,drop=F] # not a matrix

Answer 1

我猜它被覆盖了F; F可以设置为变量,在这种情况下它不再是假的.始终FALSE完全写出来,不能将其设置为变量.

看到使用T&F而不是TRUE&FALSE有什么问题吗？

另外,- [R地狱,部分32年8月1日,是一个很好的基准.

> F <- 1
> test = matrix(letters[1:5]) # is a matrix
> test[5:1,,drop=F]           # not a matrix
[1] "e" "d" "c" "b" "a"
> test[5:1,,drop=FALSE]       # but this is a matrix
     [,1]
[1,] "e" 
[2,] "d" 
[3,] "c" 
[4,] "b" 
[5,] "a" 
> rm(F)
> test[5:1,,drop=F]           # now a matrix again
     [,1]
[1,] "e" 
[2,] "d" 
[3,] "c" 
[4,] "b" 
[5,] "a"