On Tue, 12 Aug 2008, Mike Prager wrote:
rcoder <[EMAIL PROTECTED]> 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
Or
is.na(a) <- a==0
Chuck
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
* Opinions expressed are personal and not represented otherwise.
* Any use of tradenames does not constitute a NOAA endorsement.
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Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:[EMAIL PROTECTED] UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
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