Scalar-class: Arrow scalars

In arrow: Integration to 'Apache' 'Arrow'

Arrow scalars

Description

A Scalar holds a single value of an Arrow type.

Factory

The Scalar$create() factory method instantiates a Scalar and takes the following arguments:

• x: an R vector, list, or data.frame

• type: an optional data type for x. If omitted, the type will be inferred from the data.

Usage

a <- Scalar$create(x)
length(a)

print(a)
a == a

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

• ⁠$cast(target_type, safe = TRUE, options = cast_options(safe))⁠: cast value to a different type

Examples

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()

arrow documentation built on Sept. 11, 2024, 8:02 p.m.