Element-wise mean in R

r mean
Zhang18 picture Zhang18 · Aug 16, 2010 · Viewed 18k times · Source

In R, I have two vectors:

a <- c(1, 2, 3, 4)
b <- c(NA, 6, 7, 8)

How do I find the element-wise mean of the two vectors, removing NA, without a loop? i.e. I want to get the vector of 

(1, 4, 5, 6)

I know the function mean(), I know the argument na.rm = 1. But I don't know how to put things together. To be sure, in reality I have thousands of vectors with NA appearing at various places, so any dimension-dependent solution wouldn't work. Thanks.

Answer

Greg picture Greg · Aug 16, 2010

how about: 

rowMeans(cbind(a, b), na.rm=TRUE)

or

colMeans(rbind(a, b), na.rm=TRUE)

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