applyby: Apply a function to each group

In basetable: Fast and Memory-Efficient Base R Table Manipulation

Apply a function to each group

Description

Apply a function to each group

Usage

applyby(data, by, fun, ..., bind = FALSE, id = ".group")

Arguments

data	A data.frame.
by	Character vector of column names identifying groups or join keys.
fun	Function applied to each element, column, or group.
...	Additional arguments (unused, or passed through depending on the function).
bind	Combine the per-group results into a single table.
id	Optional name for a source identifier column.

Value

A list of per-group results, or a combined table when bind = TRUE.

basetable documentation built on Sept. 18, 2026, 9:13 a.m.