list_unlister: Unlists Columns of Lists by Combinations of Values
In mrdwab/SOfun: Functions From Answers to R Questions on Stack Overflow

Description Usage Arguments Value Author(s) References Examples

Unlists columns of lists by row creating combinations of values in the process.

1	list_unlister(indt, addRN = TRUE)

`indt`	The input `data.table`. The input can also be a `list`, possibly with elements of different lengths.
`addRN`	Logical. Should a column named "rn" be added to the `data.table`? Such a column is required, so if it does not already exist, it is suggested to keep this set to `TRUE`, the default.

A data.table.

Ananda Mahto

http://stackoverflow.com/q/23217958/1270695

L1 <- list(list("A", c("B", "C")), list(1:2, 1:3))
list_unlister(L1)

## Note the NULLs and the shorter length of the first list item
L2 <- list(V1 = list("A", c("A", "B"), "X", NULL),
V2 = list(1, c(1, 2, 3), c(1, 2), c(1, 2, 3, 4), 1),
V3 = list(c("a", "b"), "c", "d", c("e", "f"), c("g", "h", "i")))
list_unlister(L2)

DT <- data.table::data.table(
x1 = list("A", c("A", "B"), "X", NULL, c("Z", "W")),
x2 = list(1, c(1, 2, 3), c(1, 2), c(1, 2, 3, 4), 1),
x3 = list(c("a", "b"), "c", "d", c("e", "f"), c("g", "h", "i")))
list_unlister(DT)