1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
#' @include arrow-datum.R
#' @title Arrow scalars
#' @usage NULL
#' @format NULL
#' @docType class
#'
#' @description A `Scalar` holds a single value of an Arrow type.
#'
#' @section Methods:
#' `$ToString()`: convert to a string
#' `$as_vector()`: convert to an R vector
#' `$as_array()`: convert to an Arrow `Array`
#' `$Equals(other)`: is this Scalar equal to `other`
#' `$ApproxEquals(other)`: is this Scalar approximately equal to `other`
#' `$is_valid`: is this Scalar valid
#' `$null_count`: number of invalid values - 1 or 0
#' `$type`: Scalar type
#'
#' @name Scalar
#' @rdname Scalar
#' @examplesIf arrow_available()
#' Scalar$create(pi)
#' Scalar$create(404)
#' # If you pass a vector into Scalar$create, you get a list containing your items
#' Scalar$create(c(1, 2, 3))
#'
#' # Comparisons
#' my_scalar <- Scalar$create(99)
#' my_scalar$ApproxEquals(Scalar$create(99.00001)) # FALSE
#' my_scalar$ApproxEquals(Scalar$create(99.000009)) # TRUE
#' my_scalar$Equals(Scalar$create(99.000009)) # FALSE
#' my_scalar$Equals(Scalar$create(99L)) # FALSE (types don't match)
#'
#' my_scalar$ToString()
#' @export
Scalar <- R6Class("Scalar",
inherit = ArrowDatum,
# TODO: document the methods
public = list(
ToString = function() Scalar__ToString(self),
type_id = function() Scalar__type(self)$id,
as_vector = function() Scalar__as_vector(self),
as_array = function(length = 1L) MakeArrayFromScalar(self, as.integer(length)),
Equals = function(other, ...) {
inherits(other, "Scalar") && Scalar__Equals(self, other)
},
ApproxEquals = function(other, ...) {
inherits(other, "Scalar") && Scalar__ApproxEquals(self, other)
}
),
active = list(
is_valid = function() Scalar__is_valid(self),
null_count = function() sum(!self$is_valid),
type = function() Scalar__type(self)
)
)
Scalar$create <- function(x, type = NULL) {
if (is.null(x)) {
x <- vctrs::unspecified(1)
} else if (length(x) != 1 && !is.data.frame(x)) {
# Wrap in a list type
x <- list(x)
}
Array__GetScalar(Array$create(x, type = type), 0)
}
#' @rdname array
#' @usage NULL
#' @format NULL
#' @export
StructScalar <- R6Class("StructScalar",
inherit = Scalar,
public = list(
field = function(i) StructScalar__field(self, i),
GetFieldByName = function(name) StructScalar__GetFieldByName(self, name)
)
)
#' @export
length.Scalar <- function(x) 1L
#' @export
sort.Scalar <- function(x, decreasing = FALSE, ...) x
|
