rowMedians {Biobase}R Documentation

Calculates the median for each row in a matrix

Description

Calculates the median for each row in a matrix.

Usage

rowMedians(imat, na.rm=FALSE)

Arguments

imat

A numeric matrix.

na.rm

If TRUE, NAs are excluded before calculating the medians, otherwise not.

...

Not use.

Value

Returns a double vector of length equal to number of rows in x.

Missing values

Missing values are excluded before calculating the medians.

Benchmarking

This implementation is optimized for speed and memory to calculate. As the example shows, this implementation is roughly 3-10 times faster than using apply(x, MARGIN=1, FUN=medians). As the example might show, the rowQ() does not (have to) handle missing values, and is therefore in some cases faster.

Author(s)

Henrik Bengtsson

See Also

See rowMeans() in colSums().

Examples

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)))

[Package Biobase version 2.14.0 Index]