Struct arrow_array::array::FixedSizeListArray

source ·
pub struct FixedSizeListArray { /* private fields */ }
Expand description

An array of [fixed length lists], similar to JSON arrays (e.g. ["A", "B"]).

Lists are represented using a values child array where each list has a fixed size of value_length.

Use FixedSizeListBuilder to construct a FixedSizeListArray.

§Representation

A FixedSizeListArray can represent a list of values of any other supported Arrow type. Each element of the FixedSizeListArray itself is a list which may contain NULL and non-null values, or may itself be NULL.

For example, this FixedSizeListArray stores lists of strings:

┌─────────────┐
│    [A,B]    │
├─────────────┤
│    NULL     │
├─────────────┤
│   [C,NULL]  │
└─────────────┘

The values of this FixedSizeListArrays are stored in a child StringArray where logical null values take up values_length slots in the array as shown in the following diagram. The logical values are shown on the left, and the actual FixedSizeListArray encoding on the right

                                ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┐
                                                        ┌ ─ ─ ─ ─ ─ ─ ─ ─┐    
 ┌─────────────┐                │     ┌───┐               ┌───┐ ┌──────┐      │
 │   [A,B]     │                      │ 1 │             │ │ 1 │ │  A   │ │ 0  
 ├─────────────┤                │     ├───┤               ├───┤ ├──────┤      │
 │    NULL     │                      │ 0 │             │ │ 1 │ │  B   │ │ 1  
 ├─────────────┤                │     ├───┤               ├───┤ ├──────┤      │
 │  [C,NULL]   │                      │ 1 │             │ │ 0 │ │ ???? │ │ 2  
 └─────────────┘                │     └───┘               ├───┤ ├──────┤      │
                                                        | │ 0 │ │ ???? │ │ 3  
 Logical Values                 │   Validity              ├───┤ ├──────┤      │
                                    (nulls)             │ │ 1 │ │  C   │ │ 4  
                                │                         ├───┤ ├──────┤      │
                                                        │ │ 0 │ │ ???? │ │ 5  
                                │                         └───┘ └──────┘      │
                                                        │     Values     │    
                                │   FixedSizeListArray        (Array)         │
                                                        └ ─ ─ ─ ─ ─ ─ ─ ─┘    
                                └ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┘

§Example

// Construct a value array
let value_data = ArrayData::builder(DataType::Int32)
    .len(9)
    .add_buffer(Buffer::from_slice_ref(&[0, 1, 2, 3, 4, 5, 6, 7, 8]))
    .build()
    .unwrap();
let list_data_type = DataType::FixedSizeList(
    Arc::new(Field::new("item", DataType::Int32, false)),
    3,
);
let list_data = ArrayData::builder(list_data_type.clone())
    .len(3)
    .add_child_data(value_data.clone())
    .build()
    .unwrap();
let list_array = FixedSizeListArray::from(list_data);
let list0 = list_array.value(0);
let list1 = list_array.value(1);
let list2 = list_array.value(2);

assert_eq!( &[0, 1, 2], list0.as_any().downcast_ref::<Int32Array>().unwrap().values());
assert_eq!( &[3, 4, 5], list1.as_any().downcast_ref::<Int32Array>().unwrap().values());
assert_eq!( &[6, 7, 8], list2.as_any().downcast_ref::<Int32Array>().unwrap().values());

fixed size arrays

Implementations§

source§

impl FixedSizeListArray

source

pub fn new( field: FieldRef, size: i32, values: ArrayRef, nulls: Option<NullBuffer>, ) -> Self

Create a new FixedSizeListArray with size element size, panicking on failure

§Panics

Panics if Self::try_new returns an error

source

pub fn try_new( field: FieldRef, size: i32, values: ArrayRef, nulls: Option<NullBuffer>, ) -> Result<Self, ArrowError>

Create a new FixedSizeListArray from the provided parts, returning an error on failure

§Errors
  • size < 0
  • values.len() / size != nulls.len()
  • values.data_type() != field.data_type()
  • !field.is_nullable() && !nulls.expand(size).contains(values.logical_nulls())
source

pub fn new_null(field: FieldRef, size: i32, len: usize) -> Self

Create a new FixedSizeListArray of length len where all values are null

§Panics

Panics if

  • size < 0
  • size * len would overflow usize
source

pub fn into_parts(self) -> (FieldRef, i32, ArrayRef, Option<NullBuffer>)

Deconstruct this array into its constituent parts

source

pub fn values(&self) -> &ArrayRef

Returns a reference to the values of this list.

source

pub fn value_type(&self) -> DataType

Returns a clone of the value type of this list.

source

pub fn value(&self, i: usize) -> ArrayRef

Returns ith value of this list array.

source

pub fn value_offset(&self, i: usize) -> i32

Returns the offset for value at index i.

Note this doesn’t do any bound checking, for performance reason.

source

pub const fn value_length(&self) -> i32

Returns the length for an element.

All elements have the same length as the array is a fixed size.

source

pub fn slice(&self, offset: usize, len: usize) -> Self

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

source

pub fn from_iter_primitive<T, P, I>(iter: I, length: i32) -> Self
where T: ArrowPrimitiveType, P: IntoIterator<Item = Option<<T as ArrowPrimitiveType>::Native>>, I: IntoIterator<Item = Option<P>>,

Creates a FixedSizeListArray from an iterator of primitive values

§Example

let data = vec![
   Some(vec![Some(0), Some(1), Some(2)]),
   None,
   Some(vec![Some(3), None, Some(5)]),
   Some(vec![Some(6), Some(7), Some(45)]),
];
let list_array = FixedSizeListArray::from_iter_primitive::<Int32Type, _, _>(data, 3);
println!("{:?}", list_array);
source

pub fn iter(&self) -> FixedSizeListIter<'_>

constructs a new iterator

Trait Implementations§

source§

impl Array for FixedSizeListArray

source§

fn as_any(&self) -> &dyn Any

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

fn to_data(&self) -> ArrayData

Returns the underlying data of this array
source§

fn into_data(self) -> ArrayData

Returns the underlying data of this array Read more
source§

fn data_type(&self) -> &DataType

Returns a reference to the DataType of this array. Read more
source§

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

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

fn len(&self) -> usize

Returns the length (i.e., number of elements) of this array. Read more
source§

fn is_empty(&self) -> bool

Returns whether this array is empty. Read more
source§

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. Read more
source§

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

Returns the null buffer of this array if any. Read more
source§

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.
source§

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.
source§

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

Returns a potentially computed NullBuffer that represents the logical null values of this array, if any. Read more
source§

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

Returns whether the element at index is null according to Array::nulls Read more
source§

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

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

fn null_count(&self) -> usize

Returns the total number of physical null values in this array. Read more
source§

fn is_nullable(&self) -> bool

Returns false if the array is guaranteed to not contain any logical nulls Read more
source§

impl<'a> ArrayAccessor for &'a FixedSizeListArray

§

type Item = Arc<dyn Array>

The Arrow type of the element being accessed.
source§

fn value(&self, index: usize) -> Self::Item

Returns the element at index i Read more
source§

unsafe fn value_unchecked(&self, index: usize) -> Self::Item

Returns the element at index i Read more
source§

impl ArrayAccessor for FixedSizeListArray

§

type Item = Arc<dyn Array>

The Arrow type of the element being accessed.
source§

fn value(&self, index: usize) -> Self::Item

Returns the element at index i Read more
source§

unsafe fn value_unchecked(&self, index: usize) -> Self::Item

Returns the element at index i Read more
source§

impl Clone for FixedSizeListArray

source§

fn clone(&self) -> FixedSizeListArray

Returns a copy of the value. Read more
1.0.0 · source§

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

Performs copy-assignment from source. Read more
source§

impl Debug for FixedSizeListArray

source§

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

Formats the value using the given formatter. Read more
source§

impl From<ArrayData> for FixedSizeListArray

source§

fn from(data: ArrayData) -> Self

Converts to this type from the input type.
source§

impl From<FixedSizeListArray> for ArrayData

source§

fn from(array: FixedSizeListArray) -> Self

Converts to this type from the input type.
source§

impl From<FixedSizeListArray> for FixedSizeBinaryArray

Creates a FixedSizeBinaryArray from FixedSizeList<u8> array

source§

fn from(v: FixedSizeListArray) -> Self

Converts to this type from the input type.
source§

impl<OffsetSize: OffsetSizeTrait> From<FixedSizeListArray> for GenericListArray<OffsetSize>

source§

fn from(value: FixedSizeListArray) -> Self

Converts to this type from the input type.
source§

impl PartialEq for FixedSizeListArray

source§

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

Tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

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

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

Auto Trait Implementations§

Blanket Implementations§

source§

impl<T> Any for T
where T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for T
where T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> CloneToUninit for T
where T: Clone,

source§

default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
source§

impl<T> Datum for T
where T: Array,

source§

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

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

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for T
where U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<T> ToOwned for T
where T: Clone,

§

type Owned = T

The resulting type after obtaining ownership.
source§

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
source§

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.