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GLDEX (version 2.0.0.9.3)

fun.mApply: Applying functions based on an index for a matrix.

Description

This is a generic function that can be used to find mean, variance, sum or other operations according to some index imposed on the matrix or vector.

Usage

fun.mApply(X, INDEX, FUN = NULL, ..., simplify = TRUE)

Value

If FUN returns more than one number, fun.mApply returns a matrix with rows corresponding to unique values of INDEX.

Arguments

X

Matrix with n rows.

INDEX

Vector or list of vectors of length n.

FUN

Function to operate on submatrices of X by INDEX

...

Arguments to function.

simplify

Set as TRUE by default, see sapply fo details.

Author

Tony Plate

Examples

Run this code
# Finding the row medians of a matrix (matrix(1:20,nrow=5))
fun.mApply(matrix(1:20,nrow=5),list(1:5),median)

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