purrr (version 0.2.4)

flatten: Flatten a list of lists into a simple vector.

Description

These functions remove a level hierarchy from a list. They are similar to unlist(), only ever remove a single layer of hierarchy, and are type-stable so you always know what the type of the output is.

Usage

flatten(.x)
flatten_lgl(.x)
flatten_int(.x)
flatten_dbl(.x)
flatten_chr(.x)
flatten_dfr(.x, .id = NULL)
flatten_dfc(.x)

Arguments

.x

A list of flatten. The contents of the list can be anything for flatten (as a list is returned), but the contents must match the type for the other functions.

.id

If not NULL a variable with this name will be created giving either the name or the index of the data frame.

Value

flatten() returns a list, flatten_lgl() a logical vector, flatten_int() an integer vector, flatten_dbl() a double vector, and flatten_chr() a character vector.

flatten_dfr() and flatten_dfc() return data frames created by row-binding and column-binding respectively. They require dplyr to be installed.

Examples

# NOT RUN {
x <- rerun(2, sample(4))
x
x %>% flatten()
x %>% flatten_int()

# You can use flatten in conjunction with map
x %>% map(1L) %>% flatten_int()
# But it's more efficient to use the typed map instead.
x %>% map_int(1L)
# }