Scalar-class function

Arrow scalars

A Scalar holds a single value of an Arrow type. class

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()