count: Count observations by group

In vectra: Columnar Query Engine for Larger-than-RAM Data

Count observations by group

Description

Count observations by group

Usage

count(x, ..., wt = NULL, sort = FALSE, name = NULL)

tally(x, wt = NULL, sort = FALSE, name = NULL)

Arguments

x	A vectra_node object.
...	Grouping columns (unquoted).
wt	Column to weight by (unquoted). If NULL, counts rows.
sort	If TRUE, sort output in descending order of n.
name	Name of the count column (default "n").

Details

Equivalent to group_by(...) |> summarise(n = n()). When wt is provided, uses sum(wt) instead of n(). When sort = TRUE, results are sorted in descending order of the count column.

Value

A vectra_node with group columns and a count column.

Examples

f <- tempfile(fileext = ".vtr")
write_vtr(mtcars, f)
tbl(f) |> count(cyl) |> collect()
unlink(f)

vectra documentation built on May 8, 2026, 9:06 a.m.