sd for each column
This function is speed optimized sd per column of a matrix or data.frame and treats each column as independent set of data for sd (equiv to apply(dat,2,sd)). NAs are ignored from data. Speed improvements may be seen at more than 100 columns
sd
apply(dat,2,sd)
colSds(dat, silent = FALSE, debug = FALSE, callFrom = NULL)
dat
silent
debug
callFrom
numeric vector of sd values
set.seed(2016); dat1 <- matrix(c(runif(200) +rep(1:10,20)), ncol=10) colSds(dat1)
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