Enum datafusion::scalar::ScalarValue

pub enum ScalarValue {
    Boolean(Option<bool>),
    Float32(Option<f32>),
    Float64(Option<f64>),
    Int8(Option<i8>),
    Int16(Option<i16>),
    Int32(Option<i32>),
    Int64(Option<i64>),
    UInt8(Option<u8>),
    UInt16(Option<u16>),
    UInt32(Option<u32>),
    UInt64(Option<u64>),
    Utf8(Option<String>),
    LargeUtf8(Option<String>),
    Binary(Option<Vec<u8>>),
    LargeBinary(Option<Vec<u8>>),
    List(Option<Box<Vec<ScalarValue>>>, Box<DataType>),
    Date32(Option<i32>),
    Date64(Option<i64>),
    TimestampSecond(Option<i64>),
    TimestampMillisecond(Option<i64>),
    TimestampMicrosecond(Option<i64>),
    TimestampNanosecond(Option<i64>),
    IntervalYearMonth(Option<i32>),
    IntervalDayTime(Option<i64>),
    Struct(Option<Box<Vec<ScalarValue>>>, Box<Vec<Field>>),
}

Represents a dynamically typed, nullable single value. This is the single-valued counter-part of arrow’s Array.

Variants

Boolean(Option<bool>)

true or false value

Tuple Fields of Boolean

0: Option<bool>

Float32(Option<f32>)

32bit float

Tuple Fields of Float32

0: Option<f32>

Float64(Option<f64>)

64bit float

Tuple Fields of Float64

0: Option<f64>

Int8(Option<i8>)

signed 8bit int

Tuple Fields of Int8

0: Option<i8>

Int16(Option<i16>)

signed 16bit int

Tuple Fields of Int16

0: Option<i16>

Int32(Option<i32>)

signed 32bit int

Tuple Fields of Int32

0: Option<i32>

Int64(Option<i64>)

signed 64bit int

Tuple Fields of Int64

0: Option<i64>

UInt8(Option<u8>)

unsigned 8bit int

Tuple Fields of UInt8

0: Option<u8>

UInt16(Option<u16>)

unsigned 16bit int

Tuple Fields of UInt16

0: Option<u16>

UInt32(Option<u32>)

unsigned 32bit int

Tuple Fields of UInt32

0: Option<u32>

UInt64(Option<u64>)

unsigned 64bit int

Tuple Fields of UInt64

0: Option<u64>

Utf8(Option<String>)

utf-8 encoded string.

Tuple Fields of Utf8

0: Option<String>

LargeUtf8(Option<String>)

utf-8 encoded string representing a LargeString’s arrow type.

Tuple Fields of LargeUtf8

0: Option<String>

Binary(Option<Vec<u8>>)

binary

Tuple Fields of Binary

0: Option<Vec<u8>>

LargeBinary(Option<Vec<u8>>)

large binary

Tuple Fields of LargeBinary

0: Option<Vec<u8>>

List(Option<Box<Vec<ScalarValue>>>, Box<DataType>)

list of nested ScalarValue (boxed to reduce size_of(ScalarValue))

Tuple Fields of List

0: Option<Box<Vec<ScalarValue>>>1: Box<DataType>

Date32(Option<i32>)

Date stored as a signed 32bit int

Tuple Fields of Date32

0: Option<i32>

Date64(Option<i64>)

Date stored as a signed 64bit int

Tuple Fields of Date64

0: Option<i64>

TimestampSecond(Option<i64>)

Timestamp Second

Tuple Fields of TimestampSecond

0: Option<i64>

TimestampMillisecond(Option<i64>)

Timestamp Milliseconds

Tuple Fields of TimestampMillisecond

0: Option<i64>

TimestampMicrosecond(Option<i64>)

Timestamp Microseconds

Tuple Fields of TimestampMicrosecond

0: Option<i64>

TimestampNanosecond(Option<i64>)

Timestamp Nanoseconds

Tuple Fields of TimestampNanosecond

0: Option<i64>

IntervalYearMonth(Option<i32>)

Interval with YearMonth unit

Tuple Fields of IntervalYearMonth

0: Option<i32>

IntervalDayTime(Option<i64>)

Interval with DayTime unit

Tuple Fields of IntervalDayTime

0: Option<i64>

Struct(Option<Box<Vec<ScalarValue>>>, Box<Vec<Field>>)

struct of nested ScalarValue (boxed to reduce size_of(ScalarValue))

Tuple Fields of Struct

0: Option<Box<Vec<ScalarValue>>>1: Box<Vec<Field>>

Implementations

impl ScalarValue

pub fn get_datatype(&self) -> DataType

Getter for the DataType of the value

pub fn arithmetic_negate(&self) -> Self

Calculate arithmetic negation for a scalar value

pub fn is_null(&self) -> bool

whether this value is null or not.

pub fn to_array(&self) -> ArrayRef

Converts a scalar value into an 1-row array.

pub fn iter_to_array(
    scalars: impl IntoIterator<Item = ScalarValue>
) -> Result<ArrayRef>

Converts an iterator of references ScalarValue into an ArrayRef corresponding to those values. For example,

Returns an error if the iterator is empty or if the ScalarValues are not all the same type

Example

use datafusion::scalar::ScalarValue;
use arrow::array::{ArrayRef, BooleanArray};

let scalars = vec![
  ScalarValue::Boolean(Some(true)),
  ScalarValue::Boolean(None),
  ScalarValue::Boolean(Some(false)),
];

// Build an Array from the list of ScalarValues
let array = ScalarValue::iter_to_array(scalars.into_iter())
  .unwrap();

let expected: ArrayRef = std::sync::Arc::new(
  BooleanArray::from(vec![
    Some(true),
    None,
    Some(false)
  ]
));

assert_eq!(&array, &expected);

pub fn to_array_of_size(&self, size: usize) -> ArrayRef

Converts a scalar value into an array of size rows.

pub fn try_from_array(array: &ArrayRef, index: usize) -> Result<Self>

Converts a value in array at index into a ScalarValue

pub fn eq_array(&self, array: &ArrayRef, index: usize) -> bool

Compares a single row of array @ index for equality with self, in an optimized fashion.

This method implements an optimized version of:

    let arr_scalar = Self::try_from_array(array, index).unwrap();
    arr_scalar.eq(self)

Performance note: the arrow compute kernels should be preferred over this function if at all possible as they can be vectorized and are generally much faster.

This function has a few narrow usescases such as hash table key comparisons where comparing a single row at a time is necessary.

Trait Implementations

impl Clone for ScalarValue

fn clone(&self) -> ScalarValue

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ScalarValue

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for ScalarValue

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<&'_ str> for ScalarValue

fn from(value: &str) -> Self

Performs the conversion.

impl From<Option<&'_ str>> for ScalarValue

fn from(value: Option<&str>) -> Self

Performs the conversion.

impl From<Option<bool>> for ScalarValue

fn from(value: Option<bool>) -> Self

Performs the conversion.

impl From<Option<f32>> for ScalarValue

fn from(value: Option<f32>) -> Self

Performs the conversion.

impl From<Option<f64>> for ScalarValue

fn from(value: Option<f64>) -> Self

Performs the conversion.

impl From<Option<i16>> for ScalarValue

fn from(value: Option<i16>) -> Self

Performs the conversion.

impl From<Option<i32>> for ScalarValue

fn from(value: Option<i32>) -> Self

Performs the conversion.

impl From<Option<i64>> for ScalarValue

fn from(value: Option<i64>) -> Self

Performs the conversion.

impl From<Option<i8>> for ScalarValue

fn from(value: Option<i8>) -> Self

Performs the conversion.

impl From<Option<u16>> for ScalarValue

fn from(value: Option<u16>) -> Self

Performs the conversion.

impl From<Option<u32>> for ScalarValue

fn from(value: Option<u32>) -> Self

Performs the conversion.

impl From<Option<u64>> for ScalarValue

fn from(value: Option<u64>) -> Self

Performs the conversion.

impl From<Option<u8>> for ScalarValue

fn from(value: Option<u8>) -> Self

Performs the conversion.

impl From<Vec<(&'_ str, ScalarValue), Global>> for ScalarValue

fn from(value: Vec<(&str, ScalarValue)>) -> Self

Performs the conversion.

impl From<bool> for ScalarValue

fn from(value: bool) -> Self

Performs the conversion.

impl From<f32> for ScalarValue

fn from(value: f32) -> Self

Performs the conversion.

impl From<f64> for ScalarValue

fn from(value: f64) -> Self

Performs the conversion.

impl From<i16> for ScalarValue

fn from(value: i16) -> Self

Performs the conversion.

impl From<i32> for ScalarValue

fn from(value: i32) -> Self

Performs the conversion.

impl From<i64> for ScalarValue

fn from(value: i64) -> Self

Performs the conversion.

impl From<i8> for ScalarValue

fn from(value: i8) -> Self

Performs the conversion.

impl From<u16> for ScalarValue

fn from(value: u16) -> Self

Performs the conversion.

impl From<u32> for ScalarValue

fn from(value: u32) -> Self

Performs the conversion.

impl From<u64> for ScalarValue

fn from(value: u64) -> Self

Performs the conversion.

impl From<u8> for ScalarValue

fn from(value: u8) -> Self

Performs the conversion.

impl FromStr for ScalarValue

type Err = Infallible

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl Hash for ScalarValue

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl Literal for ScalarValue

fn lit(&self) -> Expr

convert the value to a Literal expression

impl PartialEq<ScalarValue> for ScalarValue

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl PartialOrd<ScalarValue> for ScalarValue

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl TryFrom<&'_ DataType> for ScalarValue

fn try_from(datatype: &DataType) -> Result<Self>

Create a Null instance of ScalarValue for this datatype

type Error = DataFusionError

The type returned in the event of a conversion error.

impl TryFrom<ScalarValue> for i8

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for i16

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for bool

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for i32

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for i64

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for u8

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for u16

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for u32

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for u64

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for f32

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl TryFrom<ScalarValue> for f64

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: ScalarValue) -> Result<Self>

Performs the conversion.

impl Eq for ScalarValue