[R] multiple bases to decimal (was: comparing two matrices)

[Adrian Dusa]

On Sunday 21 January 2007 16:30, jim holtman wrote:
> I think you are computing your bases in the wrong way.  If the data
> represents 3 columns with base 3,3,2, then the multiplier has to be
> c(6,2,1) not c(9,3,1).  I think this should compute it correctly:
>
> # create a matrix of all combination of bases 3,3,2
> mat1 <- expand.grid(0:1, 0:2, 0:2)[,3:1]
> base <- c(3,3,2)  # define the bases
> # now create the multiplier
> mbase <-  c(rev(cumprod(rev(base))),1)[-1]
> # show the data
> mat1
> base
> mbase
> # combine with original
> cbind(mat1, conv=colSums(apply(mat1, 1, function(x) x*mbase)))

YES!
Thank you so much Jim, this made my day :))
Adrian


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Adrian Dusa
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