Struct arrow_array::array::StructArray

pub struct StructArray { /* private fields */ }

A nested array type where each child (called field) is represented by a separate array.

Example: Create an array from a vector of fields

use std::sync::Arc;
use arrow_array::{Array, ArrayRef, BooleanArray, Int32Array, StructArray};
use arrow_schema::{DataType, Field};

let boolean = Arc::new(BooleanArray::from(vec![false, false, true, true]));
let int = Arc::new(Int32Array::from(vec![42, 28, 19, 31]));

let struct_array = StructArray::from(vec![
    (
        Field::new("b", DataType::Boolean, false),
        boolean.clone() as ArrayRef,
    ),
    (
        Field::new("c", DataType::Int32, false),
        int.clone() as ArrayRef,
    ),
]);
assert_eq!(struct_array.column(0).as_ref(), boolean.as_ref());
assert_eq!(struct_array.column(1).as_ref(), int.as_ref());
assert_eq!(4, struct_array.len());
assert_eq!(0, struct_array.null_count());
assert_eq!(0, struct_array.offset());

Implementations

impl StructArray

pub fn column(&self, pos: usize) -> &ArrayRef

Returns the field at pos.

pub fn num_columns(&self) -> usize

Return the number of fields in this struct array

pub fn columns(&self) -> Vec<&ArrayRef>

Returns the fields of the struct array

pub fn columns_ref(&self) -> Vec<ArrayRef>

Returns child array refs of the struct array

pub fn column_names(&self) -> Vec<&str>

Return field names in this struct array

pub fn column_by_name(&self, column_name: &str) -> Option<&ArrayRef>

Return child array whose field name equals to column_name

Note: A schema can currently have duplicate field names, in which case the first field will always be selected. This issue will be addressed in ARROW-11178

Trait Implementations

impl Array for StructArray

fn len(&self) -> usize

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

fn as_any(&self) -> &dyn Any

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

fn data(&self) -> &ArrayData

Returns a reference to the underlying data of this array.

fn into_data(self) -> ArrayData

Returns the underlying data of this array.

fn data_ref(&self) -> &ArrayData

Returns a reference-counted pointer to the underlying data of this array.

fn data_type(&self) -> &DataType

Returns a reference to the DataType of this array.

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

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

fn is_empty(&self) -> bool

Returns whether this array is empty.

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.

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

Returns whether the element at index is null. When using this function on a slice, the index is relative to the slice.

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

Returns whether the element at index is not null. When using this function on a slice, the index is relative to the slice.

fn null_count(&self) -> usize

Returns the total number of null values in this array.

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.

impl Debug for StructArray

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

Formats the value using the given formatter.

impl From<&StructArray> for RecordBatch

fn from(struct_array: &StructArray) -> Self

Create a record batch from struct array, where each field of the StructArray becomes a Field in the schema.

This currently does not flatten and nested struct types

impl From<(Vec<(Field, Arc<dyn Array + 'static>), Global>, Buffer)> for StructArray

fn from(pair: (Vec<(Field, ArrayRef)>, Buffer)) -> Self

Converts to this type from the input type.

impl From<ArrayData> for StructArray

fn from(data: ArrayData) -> Self

Converts to this type from the input type.

impl From<RecordBatch> for StructArray

fn from(batch: RecordBatch) -> Self

Converts to this type from the input type.

impl From<StructArray> for ArrayData

fn from(array: StructArray) -> Self

Converts to this type from the input type.

impl From<Vec<(Field, Arc<dyn Array + 'static>), Global>> for StructArray

fn from(v: Vec<(Field, ArrayRef)>) -> Self

Converts to this type from the input type.

impl PartialEq<StructArray> for StructArray

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.

impl TryFrom<Vec<(&str, Arc<dyn Array + 'static>), Global>> for StructArray

fn try_from(values: Vec<(&str, ArrayRef)>) -> Result<Self, ArrowError>

builds a StructArray from a vector of names and arrays. This errors if the values have a different length. An entry is set to Null when all values are null.

type Error = ArrowError

The type returned in the event of a conversion error.