rowMedians: Calculates the median for each row in a matrix
In Biobase: Biobase: Base functions for Bioconductor

Description Usage Arguments Details Value Missing values Author(s) See Also Examples

Calculates the median for each row in a matrix.

1	rowMedians(x, na.rm=FALSE, ...)

`x`	A `numeric` NxK `matrix`.
`na.rm`	If `TRUE`, `NA`s are excluded first, otherwise not.
`...`	Not use.

The implementation of rowMedians() is optimized for both speed and memory. To avoid coercing to doubles (and hence memory allocation), there is a special implementation for integer matrices. That is, if x is an integer matrix, then rowMedians(as.double(x)) would require three times the memory of rowMedians(x), but all this is avoided.

Returns a numeric vector of length N.

Missing values are excluded before calculating the medians.

Henrik Bengtsson

See rowMeans() in colSums().

set.seed(1)
x <- rnorm(n=234*543)
x[sample(1:length(x), size=0.1*length(x))] <- NA
dim(x) <- c(234,543)
y1 <- rowMedians(x, na.rm=TRUE)
y2 <- apply(x, MARGIN=1, FUN=median, na.rm=TRUE)
stopifnot(all.equal(y1, y2))

x <- cbind(x1=3, x2=c(4:1, 2:5))
stopifnot(all.equal(rowMeans(x), rowMedians(x)))