d_reduce: Reduce along a dimension lazily

In delarr: Lazy Delayed Arrays with Fused Execution

Reduce along a dimension lazily

Description

For 2D arrays use dim = "rows" or "cols". For N-d arrays you can also supply a numeric axis indicating which dimension to collapse.

Usage

d_reduce(x, f = base::sum, dim = c("rows", "cols"), axis = NULL, na.rm = FALSE)

Arguments

x	A delarr.
f	A reduction function (defaults to sum).
dim	Dimension to reduce: "rows" (keep rows, collapse cols) or "cols" (keep cols, collapse rows).
axis	Integer axis to collapse (alternative to dim for N-d arrays). Takes precedence over dim when both are supplied.
na.rm	Logical; remove missing values while reducing.

Value

A delarr capturing the reduction.

Examples

mat <- matrix(1:12, nrow = 3, ncol = 4)
darr <- delarr(mat)

row_sums <- darr |> d_reduce(sum, dim = "rows") |> collect()
row_sums

col_means <- darr |> d_reduce(mean, dim = "cols") |> collect()
col_means

delarr documentation built on July 1, 2026, 1:06 a.m.