R: Column and row-wise variances and standard deviations of a...

Column and row-wise variances and standard deviations {Rfast} | R Documentation

## Column and row-wise variances and standard deviations of a matrix

### Description

Column and row-wise variances and standard deviations of a matrix

### Usage

    colVars(x, suma = NULL, std = FALSE, na.rm = FALSE, parallel = FALSE)
    rowVars(x, suma = NULL, std = FALSE, na.rm = FALSE, parallel = FALSE)

### Arguments

`x` | A matrix with the data.
`suma` | If you already have the column sums vector supply it, otherwise leave it NULL. Depricated.
`std` | A boolean variable specyfying whether you want the variances (FALSE) or the standard deviations (TRUE) of each column.
`na.rm` | TRUE or FAlSE for remove NAs if exists.
`parallel` | Should parallel implentations take place in C++? The default value is FALSE.

### Details

We found this on stackoverflow which was created by David Arenburg. We then modified the function to match the sums type formula of the variance, which is faster.

### Value

A vector with the column variances or standard deviations.

### Author(s)

Michail Tsagris

R implementation and documentation: Michail Tsagris <mtsagris@uoc.gr> and Manos Papadakis <papadakm95@gmail.com>.

### See Also

`colmeans, colMedians, colrange`

### Examples

    x <- matrix( rnorm(100 * 100), ncol = 100 )
    a2 <- colVars(x)
    x<-a2<-NULL

[Package Rfast version 2.0.4 Index]