# [R] How to remove columns of table in R recursively

Patrick Connolly p_connolly at slingshot.co.nz
Mon Sep 29 21:18:02 CEST 2008

```On Tue, 30-Sep-2008 at 12:37AM +1000, Jason Lee wrote:

|> Hi R-list,
|>
|> I would like to know how to perform any elimination of attribute (column) in
|> R.
|>
|> E.g I  have:-
|>
|> 20,21,22,23,24,25,normal
|> 1,2,3,4,5,5,normal
|> 0,1,0,2,3,4,abnormal
|> ...
|>
|> I intend to do a checking on each column:-
|>
|> If the column sum of abnormal is 0 but the column sum of normal is nonzero,
|> i wanted to eliminate this attribute. And so on and so forth observing other
|> attributes across the list. In the end, I wanted to form information as a
|> table.
|>
|> Desired Output:-
|> 21,23,24,25,normal
|> 2,4,5,5,normal
|> 1,2,3,4,abnormal
|>
|> It is some sort of removing noise from the data.

Is this the sort of thing you want to do?

> aa <- data.frame(A = 1:5, B = 12:8, C = c(0, 4, 3, 0, 1))
> aa
A  B C
1 1 12 0
2 2 11 4
3 3 10 3
4 4  9 0
5 5  8 1
> aa[!aa\$C == 0,]
A  B C
2 2 11 4
3 3 10 3
5 5  8 1

--
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.
___    Patrick Connolly
{~._.~}          		 Great minds discuss ideas
_( Y )_  	  	        Middle minds discuss events
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(_)-(_)  	                           ..... Anon

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```