[R] Basic Vector and Matrix Operations

Erik Iverson iverson at biostat.wisc.edu
Mon Jul 7 23:24:30 CEST 2008



Eric Turkheimer wrote:
> I am wondering if it is possible to perform the following two basic
> functions with primitive R functions.  I know I could write functions for
> either, but it seems as though they are probably built-in somewhere.
> 
> 1)  Fill out a vector to a desired length with missing values or zeros.  So,
> 
> x<-c(3,4,5)
> f(x,5)
> 
> 3,4,5,NA,NA
> 

For the NA case, see ?length.

> 2)  Find the [row,col] location of a particular value in a matrix, eg
> 
> x<-matrix(1:9,ncol=3)
> 
> f(x,2)
> 
> 2,1
> 
> 
> Thanks.
>



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