[R] ignoring zeros or converting to NA

[Mike Prager]

rcoder <mpdotbook at gmail.com> wrote:

> I have a matrix that has a combination of zeros and NAs. When I perform
> certain calculations on the matrix, the zeros generate "Inf" values. Is
> there a way to either convert the zeros in the matrix to NAs, or only
> perform the calculations if not zero (i.e. like using something similar to
> an !all(is.na() construct)?

Is this what you are looking for?

> # make some data
> a = matrix(c(rep(0,6), rep(2,6)), nrow = 4)
> a
     [,1] [,2] [,3]
[1,]    0    0    2
[2,]    0    0    2
[3,]    0    2    2
[4,]    0    2    2
> # change zero to NA
> is.na(a[a==0] ) <- TRUE
> a
     [,1] [,2] [,3]
[1,]   NA   NA    2
[2,]   NA   NA    2
[3,]   NA    2    2
[4,]   NA    2    2

-- 
Mike Prager, NOAA, Beaufort, NC
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