Question

I have a simple question here actually, I have a matrix (file1) of data (say 20 columns by 100 rows). which looks like this

A    B    C    D    E    F ...  
5    6    2    3    4    5 ...
5    6    2    3    4    5 ...
5    6    2    3    4    5 ...
5    6    2    3    4    5 ...
5    6    2    3    4    5 ...
.    .    .    .    .    .
.    .    .    .    .    .
.    .    .    .    .    .

I have a variable named “R” which is

R <- c(A,C,E,F)

I want to make a new matrix (file2) which contains only columns that match the variable “R”

It should be a simple command I think, but I just couldn’t find the right way to write this.
Please note that the A B C D E F are colnames, not a first row.

cheers,

Answer 1

What about this?

R = c("A","C","E","F");
file2 = file1[,R];