Struct polars_lazy::frame::LazyJsonLineReader

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pub struct LazyJsonLineReader { /* private fields */ }
Available on crate feature json only.

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impl LazyJsonLineReader

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pub fn new_paths(paths: Arc<[PathBuf]>) -> Self

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pub fn new(path: impl AsRef<Path>) -> Self

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pub fn with_row_index(self, row_index: Option<RowIndex>) -> Self

Add a row index column.

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pub fn with_ignore_errors(self, ignore_errors: bool) -> Self

Set values as Null if parsing fails because of schema mismatches.

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pub fn with_n_rows(self, num_rows: Option<usize>) -> Self

Try to stop parsing when n rows are parsed. During multithreaded parsing the upper bound n cannot be guaranteed.

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pub fn with_infer_schema_length(self, num_rows: Option<usize>) -> Self

Set the number of rows to use when inferring the json schema. the default is 100 rows. Ignored when the schema is specified explicitly using Self::with_schema. Setting to None will do a full table scan, very slow.

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pub fn with_schema(self, schema: Option<SchemaRef>) -> Self

Set the JSON file’s schema

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pub fn low_memory(self, toggle: bool) -> Self

Reduce memory usage at the expense of performance

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pub fn with_batch_size(self, batch_size: Option<NonZeroUsize>) -> Self

Trait Implementations§

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impl AnonymousScan for LazyJsonLineReader

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fn as_any(&self) -> &dyn Any

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fn scan(&self, scan_opts: AnonymousScanArgs) -> PolarsResult<DataFrame>

Creates a DataFrame from the supplied function & scan options.
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fn schema(&self, infer_schema_length: Option<usize>) -> PolarsResult<SchemaRef>

function to supply the schema. Allows for an optional infer schema argument for data sources with dynamic schemas
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fn allows_projection_pushdown(&self) -> bool

specify if the scan provider should allow projection pushdowns Read more
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fn allows_predicate_pushdown(&self) -> bool

specify if the scan provider should allow predicate pushdowns Read more
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fn allows_slice_pushdown(&self) -> bool

specify if the scan provider should allow slice pushdowns Read more
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impl Clone for LazyJsonLineReader

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fn clone(&self) -> LazyJsonLineReader

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl LazyFileListReader for LazyJsonLineReader

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fn with_rechunk(self, toggle: bool) -> Self

Rechunk the memory to contiguous chunks when parsing is done.

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fn n_rows(&self) -> Option<usize>

Try to stop parsing when n rows are parsed. During multithreaded parsing the upper bound n cannot be guaranteed.

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fn row_index(&self) -> Option<&RowIndex>

Add a row index column.

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fn finish_no_glob(self) -> PolarsResult<LazyFrame>

Get the final LazyFrame. This method assumes, that path is not a glob. Read more
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fn path(&self) -> &Path

Path of the scanned file. It can be potentially a glob pattern.
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fn paths(&self) -> &[PathBuf]

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fn with_path(self, path: PathBuf) -> Self

Set path of the scanned file. Support glob patterns.
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fn with_paths(self, paths: Arc<[PathBuf]>) -> Self

Set paths of the scanned files. Doesn’t glob patterns.
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fn with_n_rows(self, n_rows: impl Into<Option<usize>>) -> Self

Configure the row limit.
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fn with_row_index(self, row_index: impl Into<Option<RowIndex>>) -> Self

Configure the row index.
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fn rechunk(&self) -> bool

Rechunk the memory to contiguous chunks when parsing is done.
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fn finish(self) -> PolarsResult<LazyFrame>

Get the final LazyFrame.
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fn concat_impl(&self, lfs: Vec<LazyFrame>) -> PolarsResult<LazyFrame>

Recommended concatenation of LazyFrames from many input files. Read more
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fn cloud_options(&self) -> Option<&CloudOptions>

CloudOptions used to list files.
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fn iter_paths(&self) -> PolarsResult<Option<PathIterator>>

Get list of files referenced by this reader. Read more

Auto Trait Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

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fn __clone_box(&self, _: Private) -> *mut ()

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Returns the argument unchanged.

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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const ALIGN: usize = _

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type Init = T

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unsafe fn init(init: <T as Pointable>::Init) -> usize

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