Trait arrow_array::array::Array

pub trait Array: Debug + Send + Sync {
    // Required methods
    fn as_any(&self) -> &dyn Any;
    fn to_data(&self) -> ArrayData;
    fn into_data(self) -> ArrayData;
    fn data_type(&self) -> &DataType;
    fn slice(&self, offset: usize, length: usize) -> ArrayRef;
    fn len(&self) -> usize;
    fn is_empty(&self) -> bool;
    fn offset(&self) -> usize;
    fn nulls(&self) -> Option<&NullBuffer>;
    fn get_buffer_memory_size(&self) -> usize;
    fn get_array_memory_size(&self) -> usize;

    // Provided methods
    fn logical_nulls(&self) -> Option<NullBuffer> { ... }
    fn is_null(&self, index: usize) -> bool { ... }
    fn is_valid(&self, index: usize) -> bool { ... }
    fn null_count(&self) -> usize { ... }
    fn is_nullable(&self) -> bool { ... }
}

An array in the arrow columnar format

Required Methods

fn as_any(&self) -> &dyn Any

Returns the array as Any so that it can be downcasted to a specific implementation.

Example:

let id = Int32Array::from(vec![1, 2, 3, 4, 5]);
let batch = RecordBatch::try_new(
    Arc::new(Schema::new(vec![Field::new("id", DataType::Int32, false)])),
    vec![Arc::new(id)]
).unwrap();

let int32array = batch
    .column(0)
    .as_any()
    .downcast_ref::<Int32Array>()
    .expect("Failed to downcast");

fn to_data(&self) -> ArrayData

Returns the underlying data of this array

fn into_data(self) -> ArrayData

Returns the underlying data of this array

Unlike Array::to_data this consumes self, allowing it avoid unnecessary clones

fn data_type(&self) -> &DataType

Returns a reference to the DataType of this array.

Example:

use arrow_schema::DataType;
use arrow_array::{Array, Int32Array};

let array = Int32Array::from(vec![1, 2, 3, 4, 5]);

assert_eq!(*array.data_type(), DataType::Int32);

fn slice(&self, offset: usize, length: usize) -> ArrayRef

Returns a zero-copy slice of this array with the indicated offset and length.

Example:

use arrow_array::{Array, Int32Array};

let array = Int32Array::from(vec![1, 2, 3, 4, 5]);
// Make slice over the values [2, 3, 4]
let array_slice = array.slice(1, 3);

assert_eq!(&array_slice, &Int32Array::from(vec![2, 3, 4]));

fn len(&self) -> usize

Returns the length (i.e., number of elements) of this array.

Example:

use arrow_array::{Array, Int32Array};

let array = Int32Array::from(vec![1, 2, 3, 4, 5]);

assert_eq!(array.len(), 5);

fn is_empty(&self) -> bool

Returns whether this array is empty.

Example:

use arrow_array::{Array, Int32Array};

let array = Int32Array::from(vec![1, 2, 3, 4, 5]);

assert_eq!(array.is_empty(), false);

fn offset(&self) -> usize

Returns the offset into the underlying data used by this array(-slice). Note that the underlying data can be shared by many arrays. This defaults to 0.

Example:

use arrow_array::{Array, BooleanArray};

let array = BooleanArray::from(vec![false, false, true, true]);
let array_slice = array.slice(1, 3);

assert_eq!(array.offset(), 0);
assert_eq!(array_slice.offset(), 1);

fn nulls(&self) -> Option<&NullBuffer>

Returns the null buffer of this array if any.

The null buffer encodes the “physical” nulls of an array. However, some arrays can also encode nullability in their children, for example, DictionaryArray::values values or RunArray::values, or without a null buffer, such as NullArray. To determine if each element of such an array is logically null, you can use the slower Array::logical_nulls to obtain a computed mask .

fn get_buffer_memory_size(&self) -> usize

Returns the total number of bytes of memory pointed to by this array. The buffers store bytes in the Arrow memory format, and include the data as well as the validity map.

fn get_array_memory_size(&self) -> usize

Returns the total number of bytes of memory occupied physically by this array. This value will always be greater than returned by get_buffer_memory_size() and includes the overhead of the data structures that contain the pointers to the various buffers.

Provided Methods

fn logical_nulls(&self) -> Option<NullBuffer>

Returns a potentially computed NullBuffer that represent the logical null values of this array, if any.

In most cases this will be the same as Array::nulls, except for:

• DictionaryArray where DictionaryArray::values contains nulls
• RunArray where RunArray::values contains nulls
• NullArray where all indices are nulls

In these cases a logical NullBuffer will be computed, encoding the logical nullability of these arrays, beyond what is encoded in Array::nulls

fn is_null(&self, index: usize) -> bool

Returns whether the element at index is null according to Array::nulls

Note: For performance reasons, this method returns nullability solely as determined by the null buffer. This difference can lead to surprising results, for example, NullArray::is_null always returns false as the array lacks a null buffer. Similarly DictionaryArray and RunArray may encode nullability in their children. See Self::logical_nulls for more information.

Example:

use arrow_array::{Array, Int32Array, NullArray};

let array = Int32Array::from(vec![Some(1), None]);
assert_eq!(array.is_null(0), false);
assert_eq!(array.is_null(1), true);

// NullArrays do not have a null buffer, and therefore always
// return false for is_null.
let array = NullArray::new(1);
assert_eq!(array.is_null(0), false);

fn is_valid(&self, index: usize) -> bool

Returns whether the element at index is not null, the opposite of Self::is_null.

Example:

use arrow_array::{Array, Int32Array};

let array = Int32Array::from(vec![Some(1), None]);

assert_eq!(array.is_valid(0), true);
assert_eq!(array.is_valid(1), false);

fn null_count(&self) -> usize

Returns the total number of physical null values in this array.

Note: this method returns the physical null count, i.e. that encoded in Array::nulls, see Array::logical_nulls for logical nullability

Example:

use arrow_array::{Array, Int32Array};

// Construct an array with values [1, NULL, NULL]
let array = Int32Array::from(vec![Some(1), None, None]);

assert_eq!(array.null_count(), 2);

fn is_nullable(&self) -> bool

Returns false if the array is guaranteed to not contain any logical nulls

In general this will be equivalent to Array::null_count() != 0 but may differ in the presence of logical nullability, see Array::logical_nulls.

Implementations will return true unless they can cheaply prove no logical nulls are present. For example a DictionaryArray with nullable values will still return true, even if the nulls present in DictionaryArray::values are not referenced by any key, and therefore would not appear in Array::logical_nulls.

Trait Implementations

impl AsArray for dyn Array + '_

fn as_boolean_opt(&self) -> Option<&BooleanArray>

Downcast this to a BooleanArray returning None if not possible

fn as_primitive_opt<T: ArrowPrimitiveType>(&self) -> Option<&PrimitiveArray<T>>

Downcast this to a PrimitiveArray returning None if not possible

fn as_bytes_opt<T: ByteArrayType>(&self) -> Option<&GenericByteArray<T>>

Downcast this to a GenericByteArray returning None if not possible

fn as_struct_opt(&self) -> Option<&StructArray>

Downcast this to a StructArray returning None if not possible

fn as_list_opt<O: OffsetSizeTrait>(&self) -> Option<&GenericListArray<O>>

Downcast this to a GenericListArray returning None if not possible

fn as_fixed_size_binary_opt(&self) -> Option<&FixedSizeBinaryArray>

Downcast this to a FixedSizeBinaryArray returning None if not possible

fn as_fixed_size_list_opt(&self) -> Option<&FixedSizeListArray>

Downcast this to a FixedSizeListArray returning None if not possible

fn as_map_opt(&self) -> Option<&MapArray>

Downcast this to a MapArray returning None if not possible

fn as_dictionary_opt<K: ArrowDictionaryKeyType>( &self ) -> Option<&DictionaryArray<K>>

Downcast this to a DictionaryArray returning None if not possible

fn as_any_dictionary_opt(&self) -> Option<&dyn AnyDictionaryArray>

Downcasts this to a AnyDictionaryArray returning None if not possible

fn as_boolean(&self) -> &BooleanArray

Downcast this to a BooleanArray panicking if not possible

fn as_primitive<T: ArrowPrimitiveType>(&self) -> &PrimitiveArray<T>

Downcast this to a PrimitiveArray panicking if not possible

fn as_bytes<T: ByteArrayType>(&self) -> &GenericByteArray<T>

Downcast this to a GenericByteArray panicking if not possible

fn as_string_opt<O: OffsetSizeTrait>(&self) -> Option<&GenericStringArray<O>>

Downcast this to a GenericStringArray returning None if not possible

fn as_string<O: OffsetSizeTrait>(&self) -> &GenericStringArray<O>

Downcast this to a GenericStringArray panicking if not possible

fn as_binary_opt<O: OffsetSizeTrait>(&self) -> Option<&GenericBinaryArray<O>>

Downcast this to a GenericBinaryArray returning None if not possible

fn as_binary<O: OffsetSizeTrait>(&self) -> &GenericBinaryArray<O>

Downcast this to a GenericBinaryArray panicking if not possible

fn as_struct(&self) -> &StructArray

Downcast this to a StructArray panicking if not possible

fn as_list<O: OffsetSizeTrait>(&self) -> &GenericListArray<O>

Downcast this to a GenericListArray panicking if not possible

fn as_fixed_size_binary(&self) -> &FixedSizeBinaryArray

Downcast this to a FixedSizeBinaryArray panicking if not possible

fn as_fixed_size_list(&self) -> &FixedSizeListArray

Downcast this to a FixedSizeListArray panicking if not possible

fn as_map(&self) -> &MapArray

Downcast this to a MapArray panicking if not possible

fn as_dictionary<K: ArrowDictionaryKeyType>(&self) -> &DictionaryArray<K>

Downcast this to a DictionaryArray panicking if not possible

fn as_any_dictionary(&self) -> &dyn AnyDictionaryArray

Downcasts this to a AnyDictionaryArray panicking if not possible

impl Datum for &dyn Array

fn get(&self) -> (&dyn Array, bool)

Returns the value for this Datum and a boolean indicating if the value is scalar

impl Datum for dyn Array

fn get(&self) -> (&dyn Array, bool)

Returns the value for this Datum and a boolean indicating if the value is scalar

impl<T: Array> PartialEq<T> for dyn Array + '_

fn eq(&self, other: &T) -> 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 !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for dyn Array + '_

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 !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

Implementations on Foreign Types

impl<'a, T: Array> Array for &'a T

fn as_any(&self) -> &dyn Any

fn to_data(&self) -> ArrayData

fn into_data(self) -> ArrayData

fn data_type(&self) -> &DataType

fn slice(&self, offset: usize, length: usize) -> ArrayRef

fn len(&self) -> usize

fn is_empty(&self) -> bool

fn offset(&self) -> usize

fn nulls(&self) -> Option<&NullBuffer>

fn logical_nulls(&self) -> Option<NullBuffer>

fn is_null(&self, index: usize) -> bool

fn is_valid(&self, index: usize) -> bool

fn null_count(&self) -> usize

fn is_nullable(&self) -> bool

fn get_buffer_memory_size(&self) -> usize

fn get_array_memory_size(&self) -> usize

Implementors

impl Array for BooleanArray

impl Array for FixedSizeBinaryArray

impl Array for FixedSizeListArray

impl Array for MapArray

impl Array for NullArray

impl Array for StructArray

impl Array for UnionArray

impl Array for ArrayRef

Ergonomics: Allow use of an ArrayRef as an &dyn Array

impl<'a, K: ArrowDictionaryKeyType, V: Sync> Array for TypedDictionaryArray<'a, K, V>

impl<'a, R: RunEndIndexType, V: Sync> Array for TypedRunArray<'a, R, V>

impl<OffsetSize: OffsetSizeTrait> Array for GenericListArray<OffsetSize>

impl<T: ArrowDictionaryKeyType> Array for DictionaryArray<T>

impl<T: ArrowPrimitiveType> Array for PrimitiveArray<T>

impl<T: ByteArrayType> Array for GenericByteArray<T>

impl<T: RunEndIndexType> Array for RunArray<T>