slice-assign.md
In vctrs: Vector Helpers

`vec_assign()` requires recyclable value

Code
  (expect_error(vec_assign(1:3, 1:3, 1:2), class = "vctrs_error_recycle_incompatible_size")
  )
Output
  <error/vctrs_error_incompatible_size>
  Error in `vec_assign()`:
  ! Can't recycle input of size 2 to size 3.

logical subscripts must match size of indexed vector

Code
  (expect_error(vec_assign(1:2, c(TRUE, FALSE, TRUE), 5), class = "vctrs_error_subscript_size")
  )
Output
  <error/vctrs_error_subscript_size>
  Error:
  ! Can't assign elements.
  x Logical subscript must be size 1 or 2, not 3.

Code
  (expect_error(vec_assign(mtcars, c(TRUE, FALSE), mtcars[1, ]), class = "vctrs_error_subscript_size")
  )
Output
  <error/vctrs_error_subscript_size>
  Error:
  ! Can't assign elements.
  x Logical subscript must be size 1 or 32, not 2.

must assign existing elements

Code
  (expect_error(vec_assign(1:3, 5, 10), class = "vctrs_error_subscript_oob"))
Output
  <error/vctrs_error_subscript_oob>
  Error:
  ! Can't assign to elements past the end.
  i Location 5 doesn't exist.
  i There are only 3 elements.
Code
  (expect_error(vec_assign(1:3, "foo", 10), "unnamed vector"))
Output
  <error/rlang_error>
  Error in `vec_assign()`:
  ! Can't use character names to index an unnamed vector.
Code
  (expect_error(vec_slice(letters, -100) <- "foo", class = "vctrs_error_subscript_oob")
  )
Output
  <error/vctrs_error_subscript_oob>
  Error:
  ! Can't negate elements past the end.
  i Location 100 doesn't exist.
  i There are only 26 elements.
Code
  (expect_error(vec_assign(set_names(letters), "foo", "bar"), class = "vctrs_error_subscript_oob")
  )
Output
  <error/vctrs_error_subscript_oob>
  Error:
  ! Can't assign to elements that don't exist.
  x Element `foo` doesn't exist.

must assign with proper negative locations

Code
  (expect_error(vec_assign(1:3, c(-1, 1), 1:2), class = "vctrs_error_subscript_type")
  )
Output
  <error/vctrs_error_subscript_type>
  Error:
  ! Can't assign elements.
  x Negative and positive locations can't be mixed.
  i Subscript has a positive value at location 2.
Code
  (expect_error(vec_assign(1:3, c(-1, NA), 1:2), class = "vctrs_error_subscript_type")
  )
Output
  <error/vctrs_error_subscript_type>
  Error:
  ! Can't assign elements.
  x Negative locations can't have missing values.
  i Subscript has a missing value at location 2.

`vec_assign()` error args can be overridden

Code
  (expect_error(vec_assign(1:2, 1L, "x", x_arg = "foo", value_arg = "bar"),
  class = "vctrs_error_incompatible_type"))
Output
  <error/vctrs_error_cast>
  Error in `vec_assign()`:
  ! Can't convert `bar` <character> to match type of `foo` <integer>.
Code
  (expect_error(vec_assign(1:2, 1L, 1:2, value_arg = "bar"), class = "vctrs_error_recycle_incompatible_size")
  )
Output
  <error/vctrs_error_incompatible_size>
  Error in `vec_assign()`:
  ! Can't recycle `bar` (size 2) to size 1.