Struct polars_io::json::RecordBatch

pub struct RecordBatch { /* fields omitted */ }

This is supported on crate feature json only.

A two-dimensional dataset with a number of columns (Array) and rows and defined Schema.

Implementation

Cloning is O(C) where C is the number of columns.

Implementations

impl RecordBatch

pub fn try_new(
    schema: Arc<Schema>,
    columns: Vec<Arc<dyn Array + 'static>, Global>
) -> Result<RecordBatch, ArrowError>

Creates a RecordBatch from a schema and columns.

Errors

This function errors iff

• columns is empty
• the schema and column data types do not match
• columns have a different length

Example

let id_array = PrimitiveArray::from_slice([1i32, 2, 3, 4, 5]);
let schema = Arc::new(Schema::new(vec![
    Field::new("id", DataType::Int32, false)
]));

let batch = RecordBatch::try_new(
    schema,
    vec![Arc::new(id_array)]
)?;

pub fn try_new_with_options(
    schema: Arc<Schema>,
    columns: Vec<Arc<dyn Array + 'static>, Global>,
    options: &RecordBatchOptions
) -> Result<RecordBatch, ArrowError>

Creates a RecordBatch from a schema and columns, with additional options, such as whether to strictly validate field names.

See Self::try_new() for the expected conditions.

pub fn new_empty(schema: Arc<Schema>) -> RecordBatch

Creates a new empty RecordBatch.

pub fn schema(&self) -> &Arc<Schema>

Returns the Schema of the record batch.

pub fn num_columns(&self) -> usize

Returns the number of columns in the record batch.

Example

let id_array = PrimitiveArray::from_slice([1i32, 2, 3, 4, 5]);
let schema = Arc::new(Schema::new(vec![
    Field::new("id", DataType::Int32, false)
]));

let batch = RecordBatch::try_new(schema, vec![Arc::new(id_array)])?;

assert_eq!(batch.num_columns(), 1);

pub fn num_rows(&self) -> usize

Returns the number of rows in each column.

Panics

Panics if the RecordBatch contains no columns.

Example

let id_array = PrimitiveArray::from_slice([1i32, 2, 3, 4, 5]);
let schema = Arc::new(Schema::new(vec![
    Field::new("id", DataType::Int32, false)
]));

let batch = RecordBatch::try_new(schema, vec![Arc::new(id_array)])?;

assert_eq!(batch.num_rows(), 5);

pub fn column(&self, index: usize) -> &Arc<dyn Array + 'static>

Get a reference to a column’s array by index.

Panics

Panics if index is outside of 0..num_columns.

pub fn columns(&self) -> &[Arc<dyn Array + 'static>]

Get a reference to all columns in the record batch.

pub fn try_from_iter<I, F>(value: I) -> Result<RecordBatch, ArrowError> where
    I: IntoIterator<Item = (F, Arc<dyn Array + 'static>)>,
    F: AsRef<str>, 

Create a RecordBatch from an iterable list of pairs of the form (field_name, array), with the same requirements on fields and arrays as RecordBatch::try_new. This method is often used to create a single RecordBatch from arrays, e.g. for testing.

The resulting schema is marked as nullable for each column if the array for that column is has any nulls. To explicitly specify nullibility, use RecordBatch::try_from_iter_with_nullable

Example:

use std::sync::Arc;
use arrow2::array::*;
use arrow2::datatypes::DataType;
use arrow2::record_batch::RecordBatch;

let a: Arc<dyn Array> = Arc::new(Int32Array::from_slice(&[1, 2]));
let b: Arc<dyn Array> = Arc::new(Utf8Array::<i32>::from_slice(&["a", "b"]));

let record_batch = RecordBatch::try_from_iter(vec![
  ("a", a),
  ("b", b),
]);

pub fn try_from_iter_with_nullable<I, F>(
    value: I
) -> Result<RecordBatch, ArrowError> where
    I: IntoIterator<Item = (F, Arc<dyn Array + 'static>, bool)>,
    F: AsRef<str>, 

Create a RecordBatch from an iterable list of tuples of the form (field_name, array, nullable), with the same requirements on fields and arrays as RecordBatch::try_new. This method is often used to create a single RecordBatch from arrays, e.g. for testing.

Example:

use std::sync::Arc;
use arrow2::array::*;
use arrow2::datatypes::DataType;
use arrow2::record_batch::RecordBatch;

let a: Arc<dyn Array> = Arc::new(Int32Array::from_slice(&[1, 2]));
let b: Arc<dyn Array> = Arc::new(Utf8Array::<i32>::from_slice(&["a", "b"]));

// Note neither `a` nor `b` has any actual nulls, but we mark
// b an nullable
let record_batch = RecordBatch::try_from_iter_with_nullable(vec![
  ("a", a, false),
  ("b", b, true),
]);

Trait Implementations

impl Clone for RecordBatch

pub fn clone(&self) -> RecordBatch

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for RecordBatch

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

Formats the value using the given formatter.

impl From<StructArray> for RecordBatch

pub fn from(array: StructArray) -> RecordBatch

Panics iff the null count of the array is not null.

impl PartialEq<RecordBatch> for RecordBatch

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl StructuralPartialEq for RecordBatch