ceph/src/arrow/r/R/scalar.R

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   5 # to you under the Apache License, Version 2.0 (the
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   8 #
   9 #   http://www.apache.org/licenses/LICENSE-2.0
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  12 # software distributed under the License is distributed on an
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  16 # under the License.
  17
  18 #' @include arrow-datum.R
  19
  20 #' @title Arrow scalars
  21 #' @usage NULL
  22 #' @format NULL
  23 #' @docType class
  24 #'
  25 #' @description A `Scalar` holds a single value of an Arrow type.
  26 #'
  27 #' @section Methods:
  28 #'   `$ToString()`: convert to a string
  29 #'   `$as_vector()`: convert to an R vector
  30 #'   `$as_array()`: convert to an Arrow `Array`
  31 #'   `$Equals(other)`: is this Scalar equal to `other`
  32 #'   `$ApproxEquals(other)`: is this Scalar approximately equal to `other`
  33 #'   `$is_valid`: is this Scalar valid
  34 #'   `$null_count`: number of invalid values - 1 or 0
  35 #'   `$type`: Scalar type
  36 #'
  37 #' @name Scalar
  38 #' @rdname Scalar
  39 #' @examplesIf arrow_available()
  40 #' Scalar$create(pi)
  41 #' Scalar$create(404)
  42 #' # If you pass a vector into Scalar$create, you get a list containing your items
  43 #' Scalar$create(c(1, 2, 3))
  44 #'
  45 #' # Comparisons
  46 #' my_scalar <- Scalar$create(99)
  47 #' my_scalar$ApproxEquals(Scalar$create(99.00001)) # FALSE
  48 #' my_scalar$ApproxEquals(Scalar$create(99.000009)) # TRUE
  49 #' my_scalar$Equals(Scalar$create(99.000009)) # FALSE
  50 #' my_scalar$Equals(Scalar$create(99L)) # FALSE (types don't match)
  51 #'
  52 #' my_scalar$ToString()
  53 #' @export
  54 Scalar <- R6Class("Scalar",
  55   inherit = ArrowDatum,
  56   # TODO: document the methods
  57   public = list(
  58     ToString = function() Scalar__ToString(self),
  59     type_id = function() Scalar__type(self)$id,
  60     as_vector = function() Scalar__as_vector(self),
  61     as_array = function(length = 1L) MakeArrayFromScalar(self, as.integer(length)),
  62     Equals = function(other, ...) {
  63       inherits(other, "Scalar") && Scalar__Equals(self, other)
  64     },
  65     ApproxEquals = function(other, ...) {
  66       inherits(other, "Scalar") && Scalar__ApproxEquals(self, other)
  67     }
  68   ),
  69   active = list(
  70     is_valid = function() Scalar__is_valid(self),
  71     null_count = function() sum(!self$is_valid),
  72     type = function() Scalar__type(self)
  73   )
  74 )
  75 Scalar$create <- function(x, type = NULL) {
  76   if (is.null(x)) {
  77     x <- vctrs::unspecified(1)
  78   } else if (length(x) != 1 && !is.data.frame(x)) {
  79     # Wrap in a list type
  80     x <- list(x)
  81   }
  82   Array__GetScalar(Array$create(x, type = type), 0)
  83 }
  84
  85 #' @rdname array
  86 #' @usage NULL
  87 #' @format NULL
  88 #' @export
  89 StructScalar <- R6Class("StructScalar",
  90   inherit = Scalar,
  91   public = list(
  92     field = function(i) StructScalar__field(self, i),
  93     GetFieldByName = function(name) StructScalar__GetFieldByName(self, name)
  94   )
  95 )
  96
  97 #' @export
  98 length.Scalar <- function(x) 1L
  99
 100 #' @export
 101 sort.Scalar <- function(x, decreasing = FALSE, ...) x