R help - Mar 2013 - remove specific number of rows from a matrix

Dear All,
 
sorry, got stuck again on the following: let us say we have:
 
a <-c(1:5)
b <-c(6:10)
d <-cbind(a,b)
 
 
from d I would like to remove total number of rows based on the length of f. So
if:
 
f <-c(1)
 
my result is working great with the following solution:
 
d[-length(f),]
 
so I get:     a  b
[1,] 2  7
[2,] 3  8
[3,] 4  9
[4,] 5 10 but if I do: f <-c(1,2) then I get:      a  b
[1,] 1  6
[2,] 3  8
[3,] 4  9
[4,] 5 10 which tells us ideed, the code works well:-), but it is not what I
need Instead, I wanted to remove row #1 adn row#2 from the matrix to get: [1,] 3
8
[2,] 4  9
[3,] 5 10  as the end result. Please provide your insights to solve this
problem.  Any input would be greatly appreciated, thanks, Andras
	[[alternative HTML version deleted]]

Hi Andras,

what about:
> d[-(1:length(f)), ]
     a  b
[1,] 3  8
[2,] 4  9
[3,] 5 10

Best,
Gergely

On 20 March 2013 22:53, Andras Farkas <motyocska@yahoo.com> wrote:
> Dear All,
>
> sorry, got stuck again on the following: let us say we have:
>
> a <-c(1:5)
> b <-c(6:10)
> d <-cbind(a,b)
>
>
> from d I would like to remove total number of rows based on the length of
> f. So if:
>
> f <-c(1)
>
> my result is working great with the following solution:
>
> d[-length(f),]
>
> so I get:     a  b
> [1,] 2  7
> [2,] 3  8
> [3,] 4  9
> [4,] 5 10 but if I do: f <-c(1,2) then I get:      a  b
> [1,] 1  6
> [2,] 3  8
> [3,] 4  9
> [4,] 5 10 which tells us ideed, the code works well:-), but it is not what
> I need Instead, I wanted to remove row #1 adn row#2 from the matrix to
> get: [1,] 3  8
> [2,] 4  9
> [3,] 5 10  as the end result. Please provide your insights to solve this
> problem.  Any input would be greatly appreciated, thanks, Andras
>         [[alternative HTML version deleted]]
>
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
	[[alternative HTML version deleted]]

Hi,
Try:
f<-c(1,2)
?d[-seq_along(f),]
#???? a? b
#[1,] 3? 8
#[2,] 4? 9
#[3,] 5 10
A.K.




----- Original Message -----
From: Andras Farkas <motyocska at yahoo.com>
To: r-help at r-project.org
Cc: 
Sent: Wednesday, March 20, 2013 5:53 PM
Subject: [R] remove specific number of rows from a matrix

Dear All,
?
sorry, got stuck again on the following: let us say we have:
?
a <-c(1:5)
b <-c(6:10)
d <-cbind(a,b)
?
?
from d I would like to remove total number of rows based on the length of f. So
if:
?
f <-c(1)
?
my result is working great with the following solution:
?
d[-length(f),]
?
so I get:? ?  a? b
[1,] 2? 7
[2,] 3? 8
[3,] 4? 9
[4,] 5 10?but if I do:?f <-c(1,2)?then I get:?? ?  a? b
[1,] 1? 6
[2,] 3? 8
[3,] 4? 9
[4,] 5 10?which tells us ideed, the code works well:-), but it is not what I
need?Instead, I wanted to remove row #1 adn row#2 from the matrix to get:?[1,]
3? 8
[2,] 4? 9
[3,] 5 10 ?as the end result. Please provide your insights to solve this
problem. ?Any input would be greatly appreciated,?thanks,?Andras
??? [[alternative HTML version deleted]]


______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.