Trait Array
pub trait Array:
Debug
+ Send
+ Sync {
Show 18 methods
// Required methods
fn as_any(&self) -> &(dyn Any + 'static);
fn to_data(&self) -> ArrayData;
fn into_data(self) -> ArrayData;
fn data_type(&self) -> &DataType;
fn slice(&self, offset: usize, length: usize) -> Arc<dyn Array>;
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 shrink_to_fit(&mut self) { ... }
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 logical_null_count(&self) -> usize { ... }
fn is_nullable(&self) -> bool { ... }
}
Expand description
An array in the arrow columnar format
Required Methods§
fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
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 into_data(self) -> ArrayData
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 slice(&self, offset: usize, length: usize) -> Arc<dyn Array>
fn slice(&self, offset: usize, length: usize) -> Arc<dyn Array>
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
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
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
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>
fn nulls(&self) -> Option<&NullBuffer>
Returns the null buffer of this array if any.
The null buffer contains the “physical” nulls of an array, that is how the nulls are represented in the underlying arrow format.
The physical representation is efficient, but is sometimes non intuitive
for certain array types such as those with nullable child arrays like
DictionaryArray::values
, RunArray::values
or UnionArray
, or without a
null buffer, such as NullArray
.
To determine if each element of such an array is “logically” null,
use the slower Array::logical_nulls
to obtain a computed mask.
fn get_buffer_memory_size(&self) -> usize
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. Note that this does not always correspond to the exact memory usage of an array, since multiple arrays can share the same buffers or slices thereof.
fn get_array_memory_size(&self) -> usize
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 shrink_to_fit(&mut self)
fn shrink_to_fit(&mut self)
Shrinks the capacity of any exclusively owned buffer as much as possible
Shared or externally allocated buffers will be ignored, and any buffer offsets will be preserved.
fn logical_nulls(&self) -> Option<NullBuffer>
fn logical_nulls(&self) -> Option<NullBuffer>
Returns a potentially computed NullBuffer
that represents the logical
null values of this array, if any.
Logical nulls represent the values that are null in the array, regardless of the underlying physical arrow representation.
For most array types, this is equivalent to the “physical” nulls
returned by Array::nulls
. It is different for the following cases, because which
elements are null is not encoded in a single null buffer:
DictionaryArray
whereDictionaryArray::values
contains nullsRunArray
whereRunArray::values
contains nullsNullArray
where all indices are nullsUnionArray
where the selected values contains 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
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
, RunArray
and UnionArray
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
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
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 logical_null_count(&self) -> usize
fn logical_null_count(&self) -> usize
Returns the total number of logical null values in this array.
Note: this method returns the logical null count, i.e. that encoded in
Array::logical_nulls
. In general this is equivalent to Array::null_count
but may differ in the
presence of logical nullability, see Array::nulls
and Array::logical_nulls
.
§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.logical_null_count(), 2);
fn is_nullable(&self) -> bool
fn is_nullable(&self) -> bool
Returns false
if the array is guaranteed to not contain any logical nulls
This is generally equivalent to Array::logical_null_count() != 0
unless determining
the logical nulls is expensive, in which case this method can return true even for an
array without nulls.
This is also generally equivalent to Array::null_count() != 0
but may differ in the
presence of logical nullability, see Array::logical_null_count
and Array::null_count
.
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 + '_
impl AsArray for dyn Array + '_
§fn as_boolean_opt(&self) -> Option<&BooleanArray>
fn as_boolean_opt(&self) -> Option<&BooleanArray>
BooleanArray
returning None
if not possible§fn as_primitive_opt<T>(&self) -> Option<&PrimitiveArray<T>>where
T: ArrowPrimitiveType,
fn as_primitive_opt<T>(&self) -> Option<&PrimitiveArray<T>>where
T: ArrowPrimitiveType,
PrimitiveArray
returning None
if not possible§fn as_bytes_opt<T>(&self) -> Option<&GenericByteArray<T>>where
T: ByteArrayType,
fn as_bytes_opt<T>(&self) -> Option<&GenericByteArray<T>>where
T: ByteArrayType,
GenericByteArray
returning None
if not possible§fn as_byte_view_opt<T>(&self) -> Option<&GenericByteViewArray<T>>where
T: ByteViewType,
fn as_byte_view_opt<T>(&self) -> Option<&GenericByteViewArray<T>>where
T: ByteViewType,
GenericByteViewArray
returning None
if not possible§fn as_struct_opt(&self) -> Option<&StructArray>
fn as_struct_opt(&self) -> Option<&StructArray>
StructArray
returning None
if not possible§fn as_union_opt(&self) -> Option<&UnionArray>
fn as_union_opt(&self) -> Option<&UnionArray>
UnionArray
returning None
if not possible§fn as_list_opt<O>(&self) -> Option<&GenericListArray<O>>where
O: OffsetSizeTrait,
fn as_list_opt<O>(&self) -> Option<&GenericListArray<O>>where
O: OffsetSizeTrait,
GenericListArray
returning None
if not possible§fn as_fixed_size_binary_opt(&self) -> Option<&FixedSizeBinaryArray>
fn as_fixed_size_binary_opt(&self) -> Option<&FixedSizeBinaryArray>
FixedSizeBinaryArray
returning None
if not possible§fn as_fixed_size_list_opt(&self) -> Option<&FixedSizeListArray>
fn as_fixed_size_list_opt(&self) -> Option<&FixedSizeListArray>
FixedSizeListArray
returning None
if not possible§fn as_map_opt(&self) -> Option<&MapArray>
fn as_map_opt(&self) -> Option<&MapArray>
MapArray
returning None
if not possible§fn as_dictionary_opt<K>(&self) -> Option<&DictionaryArray<K>>where
K: ArrowDictionaryKeyType,
fn as_dictionary_opt<K>(&self) -> Option<&DictionaryArray<K>>where
K: ArrowDictionaryKeyType,
DictionaryArray
returning None
if not possible§fn as_any_dictionary_opt(&self) -> Option<&dyn AnyDictionaryArray>
fn as_any_dictionary_opt(&self) -> Option<&dyn AnyDictionaryArray>
AnyDictionaryArray
returning None
if not possible§fn as_boolean(&self) -> &BooleanArray
fn as_boolean(&self) -> &BooleanArray
BooleanArray
panicking if not possible§fn as_primitive<T>(&self) -> &PrimitiveArray<T>where
T: ArrowPrimitiveType,
fn as_primitive<T>(&self) -> &PrimitiveArray<T>where
T: ArrowPrimitiveType,
PrimitiveArray
panicking if not possible§fn as_bytes<T>(&self) -> &GenericByteArray<T>where
T: ByteArrayType,
fn as_bytes<T>(&self) -> &GenericByteArray<T>where
T: ByteArrayType,
GenericByteArray
panicking if not possible§fn as_string_opt<O>(&self) -> Option<&GenericByteArray<GenericStringType<O>>>where
O: OffsetSizeTrait,
fn as_string_opt<O>(&self) -> Option<&GenericByteArray<GenericStringType<O>>>where
O: OffsetSizeTrait,
GenericStringArray
returning None
if not possible§fn as_string<O>(&self) -> &GenericByteArray<GenericStringType<O>>where
O: OffsetSizeTrait,
fn as_string<O>(&self) -> &GenericByteArray<GenericStringType<O>>where
O: OffsetSizeTrait,
GenericStringArray
panicking if not possible§fn as_binary_opt<O>(&self) -> Option<&GenericByteArray<GenericBinaryType<O>>>where
O: OffsetSizeTrait,
fn as_binary_opt<O>(&self) -> Option<&GenericByteArray<GenericBinaryType<O>>>where
O: OffsetSizeTrait,
GenericBinaryArray
returning None
if not possible§fn as_binary<O>(&self) -> &GenericByteArray<GenericBinaryType<O>>where
O: OffsetSizeTrait,
fn as_binary<O>(&self) -> &GenericByteArray<GenericBinaryType<O>>where
O: OffsetSizeTrait,
GenericBinaryArray
panicking if not possible§fn as_string_view_opt(&self) -> Option<&GenericByteViewArray<StringViewType>>
fn as_string_view_opt(&self) -> Option<&GenericByteViewArray<StringViewType>>
StringViewArray
returning None
if not possible§fn as_string_view(&self) -> &GenericByteViewArray<StringViewType>
fn as_string_view(&self) -> &GenericByteViewArray<StringViewType>
StringViewArray
panicking if not possible§fn as_binary_view_opt(&self) -> Option<&GenericByteViewArray<BinaryViewType>>
fn as_binary_view_opt(&self) -> Option<&GenericByteViewArray<BinaryViewType>>
BinaryViewArray
returning None
if not possible§fn as_binary_view(&self) -> &GenericByteViewArray<BinaryViewType>
fn as_binary_view(&self) -> &GenericByteViewArray<BinaryViewType>
BinaryViewArray
panicking if not possible§fn as_byte_view<T>(&self) -> &GenericByteViewArray<T>where
T: ByteViewType,
fn as_byte_view<T>(&self) -> &GenericByteViewArray<T>where
T: ByteViewType,
GenericByteViewArray
panicking if not possible§fn as_struct(&self) -> &StructArray
fn as_struct(&self) -> &StructArray
StructArray
panicking if not possible§fn as_union(&self) -> &UnionArray
fn as_union(&self) -> &UnionArray
UnionArray
panicking if not possible§fn as_list<O>(&self) -> &GenericListArray<O>where
O: OffsetSizeTrait,
fn as_list<O>(&self) -> &GenericListArray<O>where
O: OffsetSizeTrait,
GenericListArray
panicking if not possible§fn as_fixed_size_binary(&self) -> &FixedSizeBinaryArray
fn as_fixed_size_binary(&self) -> &FixedSizeBinaryArray
FixedSizeBinaryArray
panicking if not possible§fn as_fixed_size_list(&self) -> &FixedSizeListArray
fn as_fixed_size_list(&self) -> &FixedSizeListArray
FixedSizeListArray
panicking if not possible§fn as_dictionary<K>(&self) -> &DictionaryArray<K>where
K: ArrowDictionaryKeyType,
fn as_dictionary<K>(&self) -> &DictionaryArray<K>where
K: ArrowDictionaryKeyType,
DictionaryArray
panicking if not possible§fn as_any_dictionary(&self) -> &dyn AnyDictionaryArray
fn as_any_dictionary(&self) -> &dyn AnyDictionaryArray
AnyDictionaryArray
panicking if not possibleImplementations on Foreign Types§
§impl Array for Arc<dyn Array>
impl Array for Arc<dyn Array>
Ergonomics: Allow use of an ArrayRef as an &dyn Array
§fn shrink_to_fit(&mut self)
fn shrink_to_fit(&mut self)
For shared buffers, this is a no-op.