Struct FixedRecords 

pub struct FixedRecords { /* private fields */ }

Columns of fixed-width values over one or more sources, rows long.

Implementations

impl FixedRecords

pub fn new( sources: Vec<Arc<Bytes>>, columns: Vec<ColumnLayout>, rows: usize, ) -> PolarsResult<Self>

The columns over sources, at most rows long: fewer when a source runs out first, so no read ever goes past the end of one, and a partial last record is left out rather than refused. The rows come from the sources’ lengths as they are now: a file that has grown is read by building the records again, over a fresh map, with the same columns and usize::MAX rows. No more than crate::row_index::MAX_ROWS are shown.

pub fn rows(&self) -> usize

pub fn schema(&self) -> SchemaRef

pub fn columns(&self) -> &[ColumnLayout]

pub fn sources(&self) -> &[Arc<Bytes>]

The bytes the columns read, for a reader of the raw bytes.

pub fn lazy(self: &Arc<Self>) -> LazyFrame

The frame: decoded over a row index, only what a query reaches.

pub fn window(&self, start: usize, len: usize) -> PolarsResult<DataFrame>

Rows [start, start + len), decoded now: the columns start further into the same sources, so nothing before start is decoded and no index is built.

pub fn collect(&self, rows: usize) -> PolarsResult<DataFrame>

The first rows rows of every column, decoded now.

Trait Implementations

impl Debug for FixedRecords

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

Formats the value using the given formatter.

impl RowSource for FixedRecords

fn height(&self) -> usize

Rows on hand, at most MAX_ROWS.

fn schema(&self) -> SchemaRef

fn decode(&self, column: usize, index: &IdxCa) -> PolarsResult<Column>

The schema’s columnth column for the rows index names, in that order. The index comes from the plan’s row index, so it has no nulls and every row is under Self::height; a source still refuses one that is not, rather than read past its bytes.

impl SpecRecords for FixedRecords

fn rows(&self) -> usize

fn schema(&self) -> SchemaRef

fn into_lazy(self: Arc<Self>) -> PolarsResult<LazyFrame>

The frame: a scan that decodes only what a query asks for.

fn collect(&self, rows: usize) -> PolarsResult<DataFrame>

The first rows rows, decoded now.

fn sources(&self) -> &[Arc<Bytes>]

The bytes the rows are read from, for a reader of the raw bytes.

impl Windowed for FixedRecords

fn window(&self, start: usize, len: usize) -> PolarsResult<LazyFrame>

The rows as a frame, read when it is collected.