Extract: Create an Implementation of [ For Custom Matrix-Like Types
In privefl/bigstatsr: Statistical Tools for Filebacked Big Matrices

Extract

R Documentation

Create an Implementation of [ For Custom Matrix-Like Types

Description

extract is a function that converts different index types such as negative integer vectors or logical vectors passed to the [ function as i (e.g. X[i]) or i and j (e.g. X[i, j]) into positive integer vectors. The converted indices are provided as the i parameter of extract_vector or i and j parameters of extract_matrix to facilitate implementing the extraction mechanism for custom matrix-like types.

Usage

Extract(extract_vector, extract_matrix)

Arguments

`extract_vector`	A function in the form of `⁠function(x, i)⁠` that takes a subset of `x` based on a single vector of indices `i` and returns a vector.
`extract_matrix`	A function in the form of `⁠function(x, i, j)⁠` that takes a subset of `x` based on two vectors of indices `i` and `j` and returns a matrix.