[R] boot package
Duncan Murdoch
murdoch at stats.uwo.ca
Sun Dec 5 13:02:32 CET 2004
On Sat, 4 Dec 2004 18:37:43 -0700, "Nathan Leon Pace, MD, MStat"
<n.l.pace at utah.edu> wrote:
>Hi,
>
>I using the boot package 1.2-20 on R 2.0.1.
>
>My statistics function estimates 6 parameters.
>
>In a small percentage of resampled data sets my statistics function
>doesn't produce an estimate for one parameter and the boot function
>stops with an error.
>
>I can write an ifelse(exists('parameter.estimate'), parameter.estimate,
>NA) statement within the statistic function to substitute an NA for the
>missing estimate value.
>
>However, the boot.ci function to generate CIs from the boot object
>won't accept NAs.
>
>My problem is writing code to impute a numeric value for the missing
>estimate. ifelse won't generate a numeric value if the test is mode
>logical.
The test in ifelse is always logical or is coerced to be logical, so
this isn't right. For example,
x <- c(1,2,NA)
ifelse(is.na(x), 0, x)
I suspect the problem has to do with the fact that a bare "NA" is mode
logical, but without sample code, I can't see exactly where you're
going wrong. Perhaps you got the arguments to ifelse in the wrong
order?
x <- NA
ifelse(is.na(x), 0, x) # Gives numeric result
ifelse(is.na(x), x, 0) # Gives logical result
Duncan Murdoch
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