[R] How to select a whole column? Thanks!

Jinsong Zhao
2004-08-04T11:45:26Z

Thank all of you for your kindly help.


--- Jinsong Zhao <jinsong_zh at yahoo.com> wrote:

> Dear all,
>
> I hope to remove a whole column from a data frame or matrix (> 2000
> columns). All value in the column are same. The first thing is to
> select those columns.
>
> For instance, I hope to remove the V3~6 column, for all the value in
> those colume is zero.
>
>   V3 V4 V5 V6     V7     V8     V9    V10
> 1  0  0  0  0  0.000  0.000  0.000  0.000
> 2  0  0  0  0  0.000  0.000  0.000  0.000
> 3  0  0  0  0  0.000  0.000  0.000  0.000
> 4  0  0  0  0  0.000  0.000  0.000  0.000
> 5  0  0  0  0  0.000  0.000  0.000  0.000
> 6  0  0  0  0 -0.001 -0.001 -0.001 -0.001
> 7  0  0  0  0  0.000  0.000  0.000 -0.001
> 8  0  0  0  0  0.000  0.000  0.000 -0.001
> 9  0  0  0  0 -0.009 -0.012 -0.015 -0.018
>
> I mean how to select the first four columns.
>
> Thank you very much for your consideration on this matter.
>
> Best wishes,
>
> Jinsong
>


====(Mr.) Jinsong Zhao
Ph.D. Candidate
School of the Environment
Nanjing University
22 Hankou Road, Nanjing 210093
P.R. China
E-mail: jinsong_zh at yahoo.com