matrixStats: rowMedians – R documentation

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matrixStats

rowMedians

Calculates the median for each row (column) in a matrix

Description

Calculates the median for each row (column) in a matrix.

Usage

rowMedians(x, rows = NULL, cols = NULL, na.rm = FALSE, dim. = dim(x), ...)

colMedians(x, rows = NULL, cols = NULL, na.rm = FALSE, dim. = dim(x), ...)

Arguments

`x`	A `numeric` NxK `matrix`.
`rows, cols`	A `vector` indicating subset of rows (and/or columns) to operate over. If `NULL`, no subsetting is done.
`na.rm`	If `TRUE`, `NA`s are excluded first, otherwise not.
`dim.`	An `integer` `vector` of length two specifying the dimension of `x`, also when not a `matrix`.
`...`	Not used.

Details

The implementation of rowMedians() and colMedians() 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)) (rowMedians(as.double(x))) would require three times the memory of rowMedians(x) (colMedians(x)), but all this is avoided.

Value

Returns a numeric vector of length N (K).

Author(s)

Henrik Bengtsson, Harris Jaffee