Struct Lines 

pub struct Lines { /* private fields */ }

The lines of one file or several, read where they are shown.

Implementations

impl Lines

pub fn from_bytes(parts: Vec<(String, Arc<Bytes>)>) -> Self

bytes read as lines; name is what the file column says when there are several.

pub fn from_bytes_first(parts: Vec<(String, Arc<Bytes>)>, first: usize) -> Self

Self::from_bytes, one file’s first first bytes indexed and the rest left to Self::index_more. Several files are indexed whole: a row’s place in one would move as the file before it was indexed.

pub fn whole(&self) -> bool

Whether every line of every file is indexed.

pub fn shrank(&self) -> bool

Whether the file came back shorter than it was mapped while it was indexed.

pub fn resume_indexing(&self) -> bool

Indexing set aside (Self::stop_indexing was not called: a pause leaves the reads waiting) is taken up again: whether there is more to index.

pub fn line_in_file(&self, place: usize) -> Option<usize>

Which line of its own file the row at place is, from 0: the row’s place in the table, for one file.

pub fn several(&self) -> bool

Whether the rows are of several files, each numbered on its own.

pub fn indexing(&self) -> bool

Whether lines are still being indexed behind the first rows.

pub fn stop_indexing(&self)

No more lines will be indexed: all of them are, or the indexing stopped (the dataset went). Whatever waits on them goes on with what there is.

pub fn index_more(&self, budget: usize) -> bool

Index at least budget more bytes of a file indexed in part. Returns whether every line is indexed. Holds the lines’ write lock for the step only, so rows are read between steps.

pub fn indexed_bytes(&self) -> (u64, u64)

Bytes indexed, and the bytes there are.

pub fn open(paths: &[PathBuf], follow: bool) -> Result<Self>

The files at paths, mapped and indexed. follow reads one on as it grows.

pub fn open_first(paths: &[PathBuf], follow: bool, first: usize) -> Result<Self>

Self::open, a file not followed indexed through its first first bytes.

pub fn grows(&self) -> bool

Whether lines are read on as the file grows.

pub fn rows(&self) -> usize

Rows on hand.

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

The frame: a row index decoded a column at a time. A followed file’s frame has the rows of its complete lines, moved as it grows ([bound]).

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

Rows [start, start + len), decoded now.

Trait Implementations

impl RowSource for Lines

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 Windowed for Lines

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

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