Struct StructArrayAssembler 

pub struct StructArrayAssembler {
    fields: Vec<FieldRef>,
    arrays: Vec<ArrayRef>,
    nulls: Option<NullBuffer>,
}

Assembles a StructArray from completed child arrays.

Unlike StructBuilder, which incrementally builds child arrays, this assembler combines arrays that have already been built.

Example

let names = Arc::new(StringArray::from(vec!["one", "two"])) as ArrayRef;
let values = Arc::new(Int32Array::from(vec![1, 2])) as ArrayRef;
// Create struct array with `{name: ..., value: ...}` rows
let array = StructArrayAssembler::new()
    .with_field("name", names, false)
    .with_field("value", values, false)
    .build()
    .unwrap();

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

Fields

fields: Vec<FieldRef>

arrays: Vec<ArrayRef>

nulls: Option<NullBuffer>

Implementations

impl StructArrayAssembler

pub fn new() -> Self

Creates a new empty StructArrayAssembler.

pub fn with_field( self, field_name: impl Into<String>, array: ArrayRef, nullable: bool, ) -> Self

Adds an array with a field constructed from its data type.

pub fn with_field_ref(self, field: FieldRef, array: ArrayRef) -> Self

Adds an array using a caller-supplied field.

This preserves field metadata that would be lost if the field were constructed from the array’s data type alone.

pub fn with_nulls(self, nulls: NullBuffer) -> Self

Sets the top-level null buffer for the struct array.

pub fn build(self) -> Result<StructArray, ArrowError>

Builds the StructArray.

Errors

Returns an error if the fields, child arrays, or null buffer have incompatible data types or lengths.

Trait Implementations

impl Clone for StructArrayAssembler

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StructArrayAssembler

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

Formats the value using the given formatter.

impl Default for StructArrayAssembler

fn default() -> Self

Returns the “default value” for a type.