These functions create type objects corresponding to Arrow types. Use them
when defining a schema() or as inputs to other types, like struct. Most
of these functions don't take arguments, but a few do.
int8()
int16()
int32()
int64()
uint8()
uint16()
uint32()
uint64()
float16()
halffloat()
float32()
float()
float64()
boolean()
bool()
utf8()
large_utf8()
binary()
large_binary()
fixed_size_binary(byte_width)
string()
date32()
date64()
time32(unit = c("ms", "s"))
time64(unit = c("ns", "us"))
duration(unit = c("s", "ms", "us", "ns"))
null()
timestamp(unit = c("s", "ms", "us", "ns"), timezone = "")
decimal(precision, scale)
decimal128(precision, scale)
decimal256(precision, scale)
struct(...)
list_of(type)
large_list_of(type)
fixed_size_list_of(type, list_size)byte width for FixedSizeBinary type.
For time/timestamp types, the time unit. time32() can take
either "s" or "ms", while time64() can be "us" or "ns". timestamp() can
take any of those four values.
For timestamp(), an optional time zone string.
For decimal(), decimal128(), and decimal256() the
number of significant digits the arrow decimal type can represent. The
maximum precision for decimal128() is 38 significant digits, while for
decimal256() it is 76 digits. decimal() will use it to choose which
type of decimal to return.
For decimal(), decimal128(), and decimal256() the number
of digits after the decimal point. It can be negative.
For struct(), a named list of types to define the struct columns
For list_of(), a data type to make a list-of-type
list size for FixedSizeList type.
An Arrow type object inheriting from DataType.
A few functions have aliases:
utf8() and string()
float16() and halffloat()
float32() and float()
bool() and boolean()
When called inside an arrow function, such as schema() or cast(),
double() also is supported as a way of creating a float64()
date32() creates a datetime type with a "day" unit, like the R Date
class. date64() has a "ms" unit.
uint32 (32 bit unsigned integer), uint64 (64 bit unsigned integer), and
int64 (64-bit signed integer) types may contain values that exceed the
range of R's integer type (32-bit signed integer). When these arrow objects
are translated to R objects, uint32 and uint64 are converted to double
("numeric") and int64 is converted to bit64::integer64. For int64
types, this conversion can be disabled (so that int64 always yields a
bit64::integer64 object) by setting options(arrow.int64_downcast = FALSE).
decimal128() creates a Decimal128Type. Arrow decimals are fixed-point
decimal numbers encoded as a scalar integer. The precision is the number of
significant digits that the decimal type can represent; the scale is the
number of digits after the decimal point. For example, the number 1234.567
has a precision of 7 and a scale of 3. Note that scale can be negative.
As an example, decimal128(7, 3) can exactly represent the numbers 1234.567 and
-1234.567 (encoded internally as the 128-bit integers 1234567 and -1234567,
respectively), but neither 12345.67 nor 123.4567.
decimal128(5, -3) can exactly represent the number 12345000 (encoded
internally as the 128-bit integer 12345), but neither 123450000 nor 1234500.
The scale can be thought of as an argument that controls rounding. When
negative, scale causes the number to be expressed using scientific notation
and power of 10.
decimal256() creates a Decimal256Type, which allows for higher maximum
precision. For most use cases, the maximum precision offered by Decimal128Type
is sufficient, and it will result in a more compact and more efficient encoding.
#' decimal() creates either a Decimal128Type or a Decimal256Type
depending on the value for precision. If precision is greater than 38 a
Decimal256Type is returned, otherwise a Decimal128Type.
Use decimal128() or decimal256() as the names are more informative than
decimal().
dictionary() for creating a dictionary (factor-like) type.
bool()
#> Boolean
#> bool
struct(a = int32(), b = double())
#> StructType
#> struct<a: int32, b: double>
timestamp("ms", timezone = "CEST")
#> Timestamp
#> timestamp[ms, tz=CEST]
time64("ns")
#> Time64
#> time64[ns]