col_vars: Calculate Matrix Column Variance

In slideimp: Numeric Matrices K-NN and PCA Imputation

Calculate Matrix Column Variance

Description

col_vars computes the sample variance for each column of a numeric matrix.

Usage

col_vars(mat, cores = 1)

Arguments

mat	A numeric matrix.
cores	Number of cores to use for parallel computation. Defaults to 1.

Details

Variances for columns with one unique value after dropping NA are set to NA.

Value

col_vars returns a named numeric vector of column variances.

Examples

mat <- matrix(rnorm(4 * 10), ncol = 4)
mat[1, 1] <- NA
mat[1:8, 2] <- NA
mat[1:9, 3] <- NA
mat[, 4] <- NA
mat
col_vars(mat)
apply(mat, 2, var, na.rm = TRUE)

slideimp documentation built on April 17, 2026, 1:07 a.m.