lmap*() are similar to lapply(), but they map over subset .x[i]
instead of element .x[[i]].
It allows .f to access the attributes of the encapsulating list.
This is useful for operation on the sfc column in an sf data.frame.
purrr::lmap() does similar things, but it forces the output to be a list.
mclmap*() are parallelized versions of lmap*().
Usage
lmap_lst(.x, .f, mode = c("list", "integer", "double", "character", "logical"))
lmap_lgl(.x, .f)
lmap_int(.x, .f)
lmap_dbl(.x, .f)
lmap_chr(.x, .f)
lmap_vec(.x, .f, .ptype = NULL)
mclmap_lst(.x, .f, ...)
mclmap_lgl(.x, .f, ...)
mclmap_int(.x, .f, ...)
mclmap_dbl(.x, .f, ...)
mclmap_chr(.x, .f, ...)
mclmap_vec(.x, .f, ..., .ptype = NULL)Arguments
- .x
A list.
- .f
A function to apply to each subset of
.x.- mode
Output type.
- .ptype
A prototype for the output vector.
- ...
Additional arguments passed to
parallel::mclapply().
Value
A vector of the same length as .x.
The suffix of the function name denotes the output type.
*_vec() applies purrr::list_simplify() before returning.
Examples
x = list(a = 1.0, b = 2.0)
lmap_lst(x, unlist)
#> $a
#> a
#> 1
#>
#> $b
#> b
#> 2
#>
lmap_lgl(x, is.list)
#> a b
#> TRUE TRUE
lmap_int(x, length)
#> a b
#> 1 1
lmap_dbl(x, unlist)
#> a b
#> 1 2
lmap_chr(x, names)
#> a b
#> "a" "b"
lmap_vec(x, \(.x) .x[[1L]] + 2i)
#> a b
#> 1+2i 2+2i