[R] resclaing/resampling data

[Jim Lemon]

Jim Lemon wrote:
> Jan M. Wiener wrote:
> 
>>hello,
>>I am trying to rescale a matrix according to one column in the matrix.
>>Imagine having two matrices with 2 columns each:
>>
>>mat1:
>>1    2.1  
>>2    2.2
>>3   2.2
>>4   2.4
>>5     2.7
>>6   2.9
>>
>>mat2:
>>1    1.9  
>>2    2.0
>>3   2.1
>>4   2.2
>>5     2.4
>>6   3.0
>>7.  2.8
>>
>>I now want to rescale mat2 such that the values in columns 1 are also
>>between 1 and 6 (as in mat1). Of, course the values in column 2 should
>>be rescaled accordingly (simple interpolation).
>>Are there any predefined functions in R that does such rescaling?
> 
> 
> Hi Jan,
> 
> library(plotrix)
> newmat1<-rescale(mat1,c(1,6))
> newmat2<-rescale(mat2,c(1,6))
> 
Oops, didn't read that properly:
newmat2<-cbind(rescale(mat2[,1],c(1,6)),
  rescale(mat2[,2],c(min(mat2[,2],max(mat2[,2])*6/7)))

and you can make it general by substituting:

max(mat1[,1])/max(mat2[,1]) for 6/7

Jim