pub struct LazyCsvReader { /* private fields */ }
csv
only.Implementations§
Source§impl LazyCsvReader
impl LazyCsvReader
pub fn new_paths(paths: Arc<[PathBuf]>) -> Self
pub fn new_with_sources(sources: ScanSources) -> Self
pub fn new(path: impl AsRef<Path>) -> Self
Sourcepub fn with_skip_rows_after_header(self, offset: usize) -> Self
pub fn with_skip_rows_after_header(self, offset: usize) -> Self
Skip this number of rows after the header location.
Sourcepub fn with_row_index(self, row_index: Option<RowIndex>) -> Self
pub fn with_row_index(self, row_index: Option<RowIndex>) -> Self
Add a row index column.
Sourcepub fn with_n_rows(self, num_rows: Option<usize>) -> Self
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.
Sourcepub fn with_infer_schema_length(self, num_rows: Option<usize>) -> Self
pub fn with_infer_schema_length(self, num_rows: Option<usize>) -> Self
Set the number of rows to use when inferring the csv schema.
the default is 100 rows.
Setting to None
will do a full table scan, very slow.
Sourcepub fn with_ignore_errors(self, ignore: bool) -> Self
pub fn with_ignore_errors(self, ignore: bool) -> Self
Continue with next batch when a ParserError is encountered.
Sourcepub fn with_schema(self, schema: Option<SchemaRef>) -> Self
pub fn with_schema(self, schema: Option<SchemaRef>) -> Self
Set the CSV file’s schema
Sourcepub fn with_skip_rows(self, skip_rows: usize) -> Self
pub fn with_skip_rows(self, skip_rows: usize) -> Self
Skip the first n
rows during parsing. The header will be parsed at row n
.
Sourcepub fn with_dtype_overwrite(self, schema: Option<SchemaRef>) -> Self
pub fn with_dtype_overwrite(self, schema: Option<SchemaRef>) -> Self
Overwrite the schema with the dtypes in this given Schema. The given schema may be a subset of the total schema.
Sourcepub fn with_has_header(self, has_header: bool) -> Self
pub fn with_has_header(self, has_header: bool) -> Self
Set whether the CSV file has headers
Sourcepub fn with_chunk_size(self, chunk_size: usize) -> Self
pub fn with_chunk_size(self, chunk_size: usize) -> Self
Sets the chunk size used by the parser. This influences performance. This can be used as a way to reduce memory usage during the parsing at the cost of performance.
Sourcepub fn with_separator(self, separator: u8) -> Self
pub fn with_separator(self, separator: u8) -> Self
Set the CSV file’s column separator as a byte character
Sourcepub fn with_comment_prefix(self, comment_prefix: Option<PlSmallStr>) -> Self
pub fn with_comment_prefix(self, comment_prefix: Option<PlSmallStr>) -> Self
Set the comment prefix for this instance. Lines starting with this prefix will be ignored.
Sourcepub fn with_quote_char(self, quote_char: Option<u8>) -> Self
pub fn with_quote_char(self, quote_char: Option<u8>) -> Self
Set the char
used as quote char. The default is b'"'
. If set to None
quoting is disabled.
Sourcepub fn with_eol_char(self, eol_char: u8) -> Self
pub fn with_eol_char(self, eol_char: u8) -> Self
Set the char
used as end of line. The default is b'\n'
.
Sourcepub fn with_null_values(self, null_values: Option<NullValues>) -> Self
pub fn with_null_values(self, null_values: Option<NullValues>) -> Self
Set values that will be interpreted as missing/ null.
Sourcepub fn with_missing_is_null(self, missing_is_null: bool) -> Self
pub fn with_missing_is_null(self, missing_is_null: bool) -> Self
Treat missing fields as null.
Sourcepub fn with_cache(self, cache: bool) -> Self
pub fn with_cache(self, cache: bool) -> Self
Cache the DataFrame after reading.
Sourcepub fn with_low_memory(self, low_memory: bool) -> Self
pub fn with_low_memory(self, low_memory: bool) -> Self
Reduce memory usage at the expense of performance
Sourcepub fn with_encoding(self, encoding: CsvEncoding) -> Self
pub fn with_encoding(self, encoding: CsvEncoding) -> Self
Set CsvEncoding
Sourcepub fn with_try_parse_dates(self, try_parse_dates: bool) -> Self
Available on crate feature temporal
only.
pub fn with_try_parse_dates(self, try_parse_dates: bool) -> Self
temporal
only.Automatically try to parse dates/datetimes and time.
If parsing fails, columns remain of dtype DataType::String
.
Sourcepub fn with_raise_if_empty(self, raise_if_empty: bool) -> Self
pub fn with_raise_if_empty(self, raise_if_empty: bool) -> Self
Raise an error if CSV is empty (otherwise return an empty frame)
Sourcepub fn with_truncate_ragged_lines(self, truncate_ragged_lines: bool) -> Self
pub fn with_truncate_ragged_lines(self, truncate_ragged_lines: bool) -> Self
Truncate lines that are longer than the schema.
pub fn with_decimal_comma(self, decimal_comma: bool) -> Self
pub fn with_cloud_options(self, cloud_options: Option<CloudOptions>) -> Self
Sourcepub fn with_schema_modify<F>(self, f: F) -> PolarsResult<Self>
pub fn with_schema_modify<F>(self, f: F) -> PolarsResult<Self>
Modify a schema before we run the lazy scanning.
Important! Run this function latest in the builder!
pub fn with_include_file_paths( self, include_file_paths: Option<PlSmallStr>, ) -> Self
Trait Implementations§
Source§impl Clone for LazyCsvReader
impl Clone for LazyCsvReader
Source§fn clone(&self) -> LazyCsvReader
fn clone(&self) -> LazyCsvReader
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moreSource§impl LazyFileListReader for LazyCsvReader
impl LazyFileListReader for LazyCsvReader
Source§fn with_rechunk(self, rechunk: bool) -> Self
fn with_rechunk(self, rechunk: bool) -> Self
Rechunk the memory to contiguous chunks when parsing is done.
Source§fn n_rows(&self) -> Option<usize>
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.
Source§fn cloud_options(&self) -> Option<&CloudOptions>
fn cloud_options(&self) -> Option<&CloudOptions>
CloudOptions used to list files.
Source§fn finish_no_glob(self) -> PolarsResult<LazyFrame>
fn finish_no_glob(self) -> PolarsResult<LazyFrame>
fn glob(&self) -> bool
Source§fn with_sources(self, sources: ScanSources) -> Self
fn with_sources(self, sources: ScanSources) -> Self
Source§fn with_row_index(self, row_index: impl Into<Option<RowIndex>>) -> Self
fn with_row_index(self, row_index: impl Into<Option<RowIndex>>) -> Self
Source§fn with_paths(self, paths: Arc<[PathBuf]>) -> Self
fn with_paths(self, paths: Arc<[PathBuf]>) -> Self
Auto Trait Implementations§
impl Freeze for LazyCsvReader
impl !RefUnwindSafe for LazyCsvReader
impl Send for LazyCsvReader
impl Sync for LazyCsvReader
impl Unpin for LazyCsvReader
impl !UnwindSafe for LazyCsvReader
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more