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

### Arguments

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

### Details

The implementation of `rowMedians()` is optimized for both speed and memory. To avoid coercing to `double`s (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.

### Value

Returns a `numeric` `vector` of length N.

### Missing values

Missing values are excluded before calculating the medians.

### 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 2.47.3 Index]