Compute Group Means of a Matrix — group

This function calculates the average vector for each level of a grouping variable in a given matrix.

Usage

group_means(X, margin, group)

Arguments

X: A matrix for which group means should be calculated.
margin: An integer specifying the margin to average over. Use 1 for averaging over rows, and 2 for averaging over columns.
group: A grouping variable, either a factor or an integer vector, that defines the groups to calculate the means for.

Value

A matrix with the same number of rows or columns (depending on the margin) as the input matrix X, and the number of columns or rows corresponding to the number of unique groups in the grouping variable.

Examples

# Create a random matrix
data <- matrix(rnorm(100 * 100), 100, 100)

# Define a grouping variable
groups <- factor(rep(1:5, each = 20))

# Calculate group means for each row
row_means <- group_means(data, margin = 1, group = groups)

# Calculate group means for each column
col_means <- group_means(data, margin = 2, group = groups)