[R] Converting from a dataset to a single "column"

[r user]

I have a dataset of 3 “columns” and 5 “rows”.

temp<-data.frame(col1=c(5,10,14,56,7),col2=c(4,2,8,3,34),col3=c(28,4,52,34,67))

I wish to convert this to a single “column”, with
column 1 on “top” and column 3 on “bottom”.

i.e.

5
10
14
56
7
4
2
8
3
34
28
4
52
34
67

Are there any functions that do this, and that will
work well on much larger datasets (e.g. 1000 rows,
6000 columns)?