Keep column name when select one column from a data frame/matrix in R

Question

In R, when I select only one column from a data frame/matrix, the result will become a vector and lost the column names, how can I keep the column names? For example, if I run the following code,

x <- matrix(1,3,3)
colnames(x) <- c("test1","test2","test3")
x[,1]

I will get

[1] 1 1 1

Actually, I want to get

     test1
[1,]     1
[2,]     1
[3,]     1

The following code give me exactly what I want, however, is there any easier way to do this?

x <- matrix(1,3,3)
colnames(x) <- c("test1","test2","test3")
y <- as.matrix(x[,1])
colnames(y) <- colnames(x)[1]
y

Answer 1

Use the drop argument:

> x <- matrix(1,3,3)
> colnames(x) <- c("test1","test2","test3")
> x[,1, drop = FALSE]
     test1
[1,]     1
[2,]     1
[3,]     1

Answer 2

Another possibility is to use subset:

> subset(x, select = 1)

     test1
[1,]     1
[2,]     1
[3,]     1