rapply2d: Recursively Apply a Function to a List of Data Objects

In collapse: Advanced and Fast Data Transformation

Recursively Apply a Function to a List of Data Objects

Description

rapply2d is a recursive version of lapply with three differences to rapply:

1. data frames (or other list-based objects specified in classes) are considered as atomic, not as (sub-)lists

2. FUN is applied to all 'atomic' objects in the nested list

3. the result is not simplified / unlisted.

Usage

rapply2d(l, FUN, ..., classes = "data.frame")

Arguments

l	a list.
FUN	a function that can be applied to all 'atomic' elements in l.
...	additional elements passed to FUN.
classes	character. Classes of list-based objects inside l that should be considered as atomic.

Value

A list of the same structure as l, where FUN was applied to all atomic elements and list-based objects of a class included in classes.

Note

The main reason rapply2d exists is to have a recursive function that out-of-the-box applies a function to a nested list of data frames.

For most other purposes rapply, or by extension the excellent rrapply function / package, provide more advanced functionality and greater performance.

See Also

rsplit, unlist2d, List Processing, Collapse Overview

Examples

l <- list(mtcars, list(mtcars, as.matrix(mtcars)))
rapply2d(l, fmean)
unlist2d(rapply2d(l, fmean))

collapse documentation built on Aug. 19, 2025, 1:16 a.m.