t_list: Efficient List Transpose

In collapse: Advanced and Fast Data Transformation

Efficient List Transpose

Description

t_list turns a list of lists inside-out. The performance is quite efficient regardless of the size of the list.

Usage

t_list(l)

Arguments

l	a list of lists. Elements inside the sublists can be heterogeneous, including further lists.

Value

l transposed such that the second layer of the list becomes the top layer and the top layer the second layer. See Examples.

Note

To transpose a data frame / list of atomic vectors see data.table::transpose().

See Also

rsplit, List Processing, Collapse Overview

Examples

# Homogenous list of lists
l <- list(a = list(c = 1, d = 2), b = list(c = 3, d = 4))
str(l)
str(t_list(l))

# Heterogenous case
l2 <- list(a = list(c = 1, d = letters), b = list(c = 3:10, d = list(4, e = 5)))
attr(l2, "bla") <- "abc"  # Attributes other than names are preserved
str(l2)
str(t_list(l2))

rm(l, l2)

collapse documentation built on Nov. 3, 2024, 9:08 a.m.