Experimental lifecycle

  • vec_group_id() returns an identifier for the group that each element of x falls in, constructed in the order that they appear. The number of groups is also returned as an attribute, n.

  • vec_group_pos() returns a data frame containing a key column with the unique groups, and a pos column with the positions of each group in x.

  • vec_group_rle() locates groups in x and returns them run length encoded in the order that they appear. The return value is a rcrd object with fields for the group identifiers and the run length of the corresponding group. The number of groups is also returned as an attribute, n.

vec_group_id(x)

vec_group_pos(x)

vec_group_rle(x)

Arguments

x

A vector

Value

  • vec_group_id(): An integer vector with the same size as x.

  • vec_group_pos(): A two column data frame with size equal to vec_size(vec_unique(x)).

    • A key column of type vec_ptype(x)

    • A pos column of type list_of<integer>

  • vec_group_rle(): A vctrs_group_rle rcrd object with two integer vector fields: group and length.

Note that when using vec_group_pos() for complex types, the default data.frame print method will be suboptimal, and you will want to coerce into a tibble to better understand the output.

Examples

purrr <- c("p", "u", "r", "r", "r") vec_group_id(purrr)
#> [1] 1 2 3 3 3 #> attr(,"n") #> [1] 3
vec_group_rle(purrr)
#> <vctrs_group_rle[3][n = 3]> #> [1] 1x1 2x1 3x3
groups <- mtcars[c("vs", "am")] vec_group_id(groups)
#> [1] 1 1 2 3 4 3 4 3 3 3 3 4 4 4 4 4 4 2 2 2 3 4 4 4 4 2 1 2 1 1 1 2 #> attr(,"n") #> [1] 4
group_rle <- vec_group_rle(groups) group_rle
#> <vctrs_group_rle[16][n = 4]> #> [1] 1x2 2x1 3x1 4x1 3x1 4x1 3x4 4x6 2x3 3x1 4x4 2x1 1x1 2x1 1x3 2x1
# Access fields with `field()` field(group_rle, "group")
#> [1] 1 2 3 4 3 4 3 4 2 3 4 2 1 2 1 2
field(group_rle, "length")
#> [1] 2 1 1 1 1 1 4 6 3 1 4 1 1 1 3 1
# `vec_group_id()` is equivalent to vec_match(groups, vec_unique(groups))
#> [1] 1 1 2 3 4 3 4 3 3 3 3 4 4 4 4 4 4 2 2 2 3 4 4 4 4 2 1 2 1 1 1 2
vec_group_pos(mtcars$vs)
#> key pos #> 1 0 1, 2, 5, 7, 12, 13, 14, 15, 16, 17, 22, 23, 24, 25, 27, 29, 30, 31 #> 2 1 3, 4, 6, 8, 9, 10, 11, 18, 19, 20, 21, 26, 28, 32
vec_group_pos(mtcars[c("vs", "am")])
#> key.vs key.am pos #> 1 0 1 1, 2, 27, 29, 30, 31 #> 2 1 1 3, 18, 19, 20, 26, 28, 32 #> 3 1 0 4, 6, 8, 9, 10, 11, 21 #> 4 0 0 5, 7, 12, 13, 14, 15, 16, 17, 22, 23, 24, 25
if (require("tibble")) { as_tibble(vec_group_pos(mtcars[c("vs", "am")])) }
#> # A tibble: 4 x 2 #> key$vs $am pos #> <dbl> <dbl> <list<int>> #> 1 0 1 [6] #> 2 1 1 [7] #> 3 1 0 [7] #> 4 0 0 [12]