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

rowMedians {matrixStats} | R Documentation

## 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` | An NxK `matrix` or, if `dim.` is specified, an N * K `vector`.
`rows` | A `vector` indicating subset of rows to operate over. If `NULL`, no subsetting is done.
`cols` | A `vector` indicating subset of columns to operate over. If `NULL`, no subsetting is done.
`na.rm` | If `TRUE`, missing values are excluded.
`dim.` | An `integer` `vector` of length two specifying the dimension of `x`, also when not a `matrix`. Comment: The reason for this argument being named with a period at the end is purely technical (we get a run-time error if we try to name it `dim`).
`...` | Not used.

### Details

The implementation of `rowMedians()` and `colMedians()` 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))` (`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

### See Also

See `rowWeightedMedians()` and `colWeightedMedians()` for weighted medians. For mean estimates, see `rowMeans2()` and `rowMeans()`.

[Package matrixStats version 0.59.0 Index]