R help - Feb 2006 - How to force a vector to be column or row vector?

Hi all,

I tended to use rbind, or cbind to force a vector be be deemed as a column
or row vector. This is very important if I want to do things like u' * A *
u, where u' is a row vector and u is a column vector, regardless of what
originall format  the "u" is... I want to recast it to column vector
or row
vector...  How can I do that?

----------------------------------------------------


b_hat=solve(t(X) %*% X) %*% t(X) %*% Y;

attr(b_hat, "dim")
[1] 4 1

rbind(b_hat)
       [,1]
  -4.814763
V -5.804245
  -5.122668
  -4.308326

	[[alternative HTML version deleted]]

Try this:


rbind(c(x))
cbind(c(x))
t(c(x))

On 2/2/06, Michael <comtech.usa at gmail.com>
wrote:
> Hi all,
>
> I tended to use rbind, or cbind to force a vector be be deemed as a column
> or row vector. This is very important if I want to do things like u' *
A *
> u, where u' is a row vector and u is a column vector, regardless of
what
> originall format  the "u" is... I want to recast it to column
vector or row
> vector...  How can I do that?
>
> ----------------------------------------------------
>
>
> b_hat=solve(t(X) %*% X) %*% t(X) %*% Y;
>
> attr(b_hat, "dim")
> [1] 4 1
>
> rbind(b_hat)
>       [,1]
>  -4.814763
> V -5.804245
>  -5.122668
>  -4.308326
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html
>

Hi,

Perhaps you should try the transpose function t(). It
converts a row into a column and vice versa.

HTH,

Martin Lam

--- Michael <comtech.usa at gmail.com> wrote:
> Hi all,
> 
> I tended to use rbind, or cbind to force a vector be
> be deemed as a column
> or row vector. This is very important if I want to
> do things like u' * A *
> u, where u' is a row vector and u is a column
> vector, regardless of what
> originall format  the "u" is... I want to recast it
> to column vector or row
> vector...  How can I do that?
> 
> ----------------------------------------------------
> 
> 
> b_hat=solve(t(X) %*% X) %*% t(X) %*% Y;
> 
> attr(b_hat, "dim")
> [1] 4 1
> 
> rbind(b_hat)
>        [,1]
>   -4.814763
> V -5.804245
>   -5.122668
>   -4.308326
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>

From: Gabor Grothendieck
> 
> Try this:
> 
> 
> rbind(c(x))
> cbind(c(x))
> t(c(x))
The c() is not needed above.

Also, this might be a better way of computing a quadratic form:
> x <- 1:3
> m <- matrix(sample(1:9), 3, 3)
> crossprod(crossprod(m, x), x) 
     [,1]
[1,]  202
> t(x) %*% m %*% x   # Just checking...
     [,1]
[1,]  202

In R, it usually makes little difference whether a vector is row-vector or
column-vector.

Andy

 
> On 2/2/06, Michael <comtech.usa at gmail.com> wrote:
> > Hi all,
> >
> > I tended to use rbind, or cbind to force a vector be be 
> deemed as a column
> > or row vector. This is very important if I want to do 
> things like u' * A *
> > u, where u' is a row vector and u is a column vector, 
> regardless of what
> > originall format  the "u" is... I want to recast it to 
> column vector or row
> > vector...  How can I do that?
> >
> > ----------------------------------------------------
> >
> >
> > b_hat=solve(t(X) %*% X) %*% t(X) %*% Y;
> >
> > attr(b_hat, "dim")
> > [1] 4 1
> >
> > rbind(b_hat)
> >       [,1]
> >  -4.814763
> > V -5.804245
> >  -5.122668
> >  -4.308326
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> >
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
>

On 2/2/06, Liaw, Andy <andy_liaw at merck.com>
wrote:
> From: Gabor Grothendieck
> >
> > Try this:
> >
> >
> > rbind(c(x))
> > cbind(c(x))
> > t(c(x))
>
> The c() is not needed above.
The poster asked for an expression that would work "regardless of
the original form" of the vector -- row, column or neither.  The c
gets it into a known form first.  For example:
> cbind(matrix(1,1,3))  # not a column vector!
     [,1] [,2] [,3]
[1,]    1    1    1