list_insert: Insert an element into a list.

In listr: Tools for Lists

Insert an element into a list.

Description

Insert an element into a list.

Usage

list_insert(in_list, item, index, name = NULL, pad = FALSE)

list_append(in_list, item, name = NULL)

list_prepend(in_list, item, name = NULL)

Arguments

in_list	The list to work on.
item	The item to add to the list.
index	The index to insert at.
name	Optional name for the new item.
pad	Add 'NULL' elements for too large indices?

Details

The 'index' behaves in the way that everything including the specified index will be moved one position forward. Thus, if you insert at index 2, the old item at index 2 will be moved to index 3. If 'index' is larger than the length of 'in_list' the default behaviour is to just add the new item to the end of the list, however if you specify 'pad = TRUE' then as many 'NULL' elements as needed are added to the list to insert 'item' at the specified location.

The functions 'list_append' and 'list_prepend' exist as a simple short-cut for appending and prepending to a list.

Value

A list, the same as 'in_list' but with 'item' added at 'index'.

Examples

my_list <- list(foo1 = 1:10, foo2 = LETTERS[1:10])
list_insert(my_list, rnorm(3), 2, name = "bar")

listr documentation built on Oct. 6, 2022, 5:11 p.m.