map-like functions, similar to the ones implemented in purrr:

  • map() returns the results of .f applied to .x as list. If .f is not a function, map will call [[ on all elements of .x using the value of .f as index.

  • imap() applies .f to each value of .x (passed as first argument) and its name (passed as second argument). If .x does not have names, a sequence along .x is passed as second argument instead.

  • pmap() expects .x to be a list of vectors of equal length, and then applies .f to the first element of each vector of .x, then the second element of .x, and so on.

  • map_if() applies .f to each element of .x where the predicate .p evaluates to TRUE.

  • map_at() applies .f to each element of .x referenced by .at. All other elements remain unchanged.

  • keep() keeps those elements of .x where predicate .p evaluates to TRUE.

  • discard() discards those elements of .x where predicate .p evaluates to TRUE.

  • every() is TRUE if predicate .p evaluates to TRUE for each .x.

  • some() is TRUE if predicate .p evaluates to TRUE for at least one .x.

  • detect() returns the first element where predicate .p evaluates to TRUE.

Additionally, the functions map(), imap() and pmap have type-safe variants with the following suffixes:

map(.x, .f, ...)

map_lgl(.x, .f, ...)

map_int(.x, .f, ...)

map_dbl(.x, .f, ...)

map_chr(.x, .f, ...)

map_dtr(.x, .f, ..., .fill = FALSE, .idcol = NULL)

map_dtc(.x, .f, ...)

pmap(.x, .f, ...)

pmap_lgl(.x, .f, ...)

pmap_int(.x, .f, ...)

pmap_dbl(.x, .f, ...)

pmap_chr(.x, .f, ...)

pmap_dtr(.x, .f, ..., .fill = FALSE, .idcol = NULL)

pmap_dtc(.x, .f, ...)

imap(.x, .f, ...)

imap_lgl(.x, .f, ...)

imap_int(.x, .f, ...)

imap_dbl(.x, .f, ...)

imap_chr(.x, .f, ...)

imap_dtr(.x, .f, ..., .fill = FALSE, .idcol = NULL)

imap_dtc(.x, .f, ...)

keep(.x, .f, ...)

discard(.x, .p, ...)

map_if(.x, .p, .f, ...)

map_at(.x, .at, .f, ...)

every(.x, .p, ...)

some(.x, .p, ...)

detect(.x, .p, ...)

Arguments

.x

(list() | atomic vector()).

.f

(function() | character() | integer())
Function to apply, or element to extract by name (if .f is character()) or position (if .f is integer()).

...

(any)
Additional arguments passed down to .f or .p.

.fill

(logical(1))
Passed down to data.table::rbindlist().

.idcol

(logical(1))
Passed down to data.table::rbindlist().

.p

(function() | logical())
Predicate function.

.at

(character() | integer() | logical())
Index vector.