将行作为单个列放在r中

Question

I have the following data.frame x

a d g
b e h
c f i

Note : letters are used as an example. The actual data.frame has numbers in place of letters (real data which are not in ascending order, as in this example)

I want to transform it in an unique column, by putting columns from 2 to 4 under the first. The expected result is the following

a
b
c
d
e
f
g
h
i

I tried the following code

(t(x), ncol=1, nrow=ncol(x)*nrow(x), byrow=F)

but it gives (obviously) the following

a
d 
g
b
e
h
c
f
i

Answer 1

Something like this?

X <- matrix(letters[1:9], ncol=3)
matrix(X, ncol=1)

R matrices are in column major order , so you can easily concatenate them into a single column vector with the matrix function.

Answer 2

I find stack also very useful

X <- data.frame(matrix(letters[1:9], ncol=3),stringsAsFactors=FALSE)
stack(X)[,"values",drop=FALSE]