x <- c(1, 2, NA) is.constant(x)
[1] TRUE
For data such as c(1, 1, 1, NA), I should think the safest answer should be NA, because one really doesn't know whether that last number is 1 or not.
Andy
My version is
is.constant <- function(x) {
if (is.numeric(x) & !any(is.na(x))) identical(min(x), max(x)) else FALSE
}rendering
> is.constant(c(1,1,NA))
[1] FALSE
> is.constant(c(1,1,NaN))
[1] FALSE
> is.constant(rep(c(sin(pi/2),1),10)) # TRUE
[1] TRUE
--
Dr.sc.math.Christian W. Hoffmann, http://www.wsl.ch/staff/christian.hoffmann
Mathematics + Statistical Computing e-mail: [EMAIL PROTECTED]
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