subset_by_Nindex: 'subset_by_Nindex'

In PeteHaitch/DelayedMatrixStats: Functions that Apply to Rows and Columns of 'DelayedMatrix' Objects

subset_by_Nindex

Description

subset_by_Nindex() is an internal generic function not aimed to be used directly by the user. It is basically an S4 generic for DelayedArray:::subset_by_Nindex.

Usage

subset_by_Nindex(x, Nindex)

Arguments

x	An array-like object.
Nindex	An unnamed list of subscripts as positive integer vectors, one vector per dimension in x. Empty and missing subscripts (represented by integer(0) and NULL list elements, respectively) are allowed. The subscripts can contain duplicated indices. They cannot contain NAs or non-positive values.

Details

subset_by_Nindex(x, Nindex) conceptually performs the operation x[Nindex[1], ..., Nindex[length(Nindex)]). subset_by_Nindex() methods need to support empty and missing subscripts, e.g., subset_by_Nindex(x, list(NULL, integer(0))) must return an M x 0 object of class class(x) and subset_by_Nindex(x, list(integer(0), integer(0))) a 0 x 0 object of class class(x).

Also, subscripts are allowed to contain duplicate indices so things like subset_by_Nindex(x, list(c(1:3, 3:1), 2L)) need to be supported.

Value

A object of class class(x) of the appropriate type (e.g., integer, double, etc.). For example, if x is a data.frame representing an M x N matrix of integers, ⁠subset_by_Nindex(x, list(NULL, 2L)⁠ must return its 2nd column as a data.frame with M rows and 1 column of type integer.

PeteHaitch/DelayedMatrixStats documentation built on May 6, 2024, 10:25 p.m.