[−][src]Struct arrow::json::reader::Decoder
JSON values to Arrow record batch decoder. Decoder's next_batch method takes a JSON Value iterator as input and outputs Arrow record batch.
Examples
use arrow::json::reader::{Decoder, ValueIter, infer_json_schema}; use std::fs::File; use std::io::{BufReader, Seek, SeekFrom}; let mut reader = BufReader::new(File::open("test/data/mixed_arrays.json").unwrap()); let inferred_schema = infer_json_schema(&mut reader, None).unwrap(); let batch_size = 1024; let decoder = Decoder::new(inferred_schema, batch_size, None); // seek back to start so that the original file is usable again reader.seek(SeekFrom::Start(0)).unwrap(); let mut value_reader = ValueIter::new(&mut reader, None); let batch = decoder.next_batch(&mut value_reader).unwrap().unwrap(); assert_eq!(4, batch.num_rows()); assert_eq!(4, batch.num_columns());
Implementations
impl Decoder
[src]
pub fn new(
schema: SchemaRef,
batch_size: usize,
projection: Option<Vec<String>>
) -> Self
[src]
schema: SchemaRef,
batch_size: usize,
projection: Option<Vec<String>>
) -> Self
Create a new JSON decoder from any value that implements the Iterator<Item=Result<Value>>
trait.
pub fn schema(&self) -> SchemaRef
[src]
Returns the schema of the reader, useful for getting the schema without reading record batches
pub fn next_batch<I>(&self, value_iter: &mut I) -> Result<Option<RecordBatch>> where
I: Iterator<Item = Result<Value>>,
[src]
I: Iterator<Item = Result<Value>>,
Read the next batch of records
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for Decoder
[src]
impl Send for Decoder
[src]
impl Sync for Decoder
[src]
impl Unpin for Decoder
[src]
impl UnwindSafe for Decoder
[src]
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
[src]
impl<T> From<T> for T
[src]
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
[src]
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
[src]
impl<V, T> VZip<V> for T where
V: MultiLane<T>,
V: MultiLane<T>,