Hello,
Inline.
Em 07-03-2014 11:17, David Croll escreveu:
Dear R users and friends,
I would like to ask you about the weird behaviour of a function I just
wrote. This little function should take a vector, find NAs and
substitute them for the mean of the vector, and return the normalized
value of that vector.
I've tried both <- and <<- for changing the variables.
That's what I do:
# just a vector:
b <- c(1,1,1,NA,3,2)
# my function:
normalize <- function(x) {
# copy x into new vector
xn <- x
# index of NAs
nas <- which(is.na(xn) ==TRUE)
m <- mean(xn, na.rm=TRUE)
# insert mean for NAs
xn[nas] <- m
# normalize
return((xn - mean(xn))/sd(xn))
}
# run...
normalize(b)
# here's what I get:
# [1] -0.75 -0.75 -0.75 0.00 1.75 0.50
The 4th value should be 1.6, but is 0.
No it shouldn't. The value of the 4th element should be 0. It is equal
to mean(xn, na.rm = TRUE) - mean(new xn) and this is zero.
Hope this helps,
Rui Barradas
I believe the answer to my problem is pretty obvious, but I can't see it...
Best regards,
David
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______________________________________________
[email protected] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
