[R] replacing values in a vector

[Charles Roosen]

Hi,

You can use diag() and matrix multiplication to create a matrix with the
requested rows, and assign() to store the rows as separate vectors:

	> vec <- c(3,2,6,4,7)
	> mat <- diag(vec)
	> for (i in seq_along(vec)) assign(paste("vec", letters[i],
sep="."), mat[i,])
	> vec.a
	[1] 3 0 0 0 0
	> vec.b
	[1] 0 2 0 0 0

Best regards,
Charlie Roosen
Mango Solutions


-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Karen Kotschy
Sent: 17 August 2010 12:58
To: r-help at r-project.org
Subject: [R] replacing values in a vector

Dear helpRs

Does anyone have an elegant way of doing the following:

For a given numeric vector, e.g. vec <- c(3,2,6,4,7)

Create a series of vectors where all but 1 of the values are replaced by

0's,  e.g. 

vec.a <- c(3,0,0,0,0)
vec.b <- c(0,2,0,0,0)
vec.c <- c(0,0,6,0,0)
vec.d <- c(0,0,0,4,0)
vec.e <- c(0,0,0,0,7)

I have looked at `replace', but can't think of a way of making it
produce 
the 5 lines above without a for loop.

I would also like to assign the names automatically. I can create them 
easily using paste, but how does one get R to treat the resulting 
character strings as object names to which values can be assigned?

Thanks!
Karen

---
Karen Kotschy
Centre for Water in the Environment
University of the Witwatersrand, Johannesburg, South Africa
            

-- 
This message has been scanned for viruses and\ dangerous...{{dropped:20}}