1336 lines
44 KiB
Python
1336 lines
44 KiB
Python
from __future__ import annotations
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from collections import defaultdict
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from copy import copy
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import csv
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import datetime
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from enum import Enum
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import itertools
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from typing import (
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TYPE_CHECKING,
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Any,
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Callable,
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DefaultDict,
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Hashable,
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Iterable,
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List,
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Mapping,
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Sequence,
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Tuple,
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cast,
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final,
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overload,
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)
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import warnings
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import numpy as np
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import pandas._libs.lib as lib
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import pandas._libs.ops as libops
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import pandas._libs.parsers as parsers
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from pandas._libs.parsers import STR_NA_VALUES
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from pandas._libs.tslibs import parsing
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from pandas._typing import (
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ArrayLike,
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DtypeArg,
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Scalar,
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)
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from pandas.errors import (
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ParserError,
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ParserWarning,
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)
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from pandas.util._exceptions import find_stack_level
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from pandas.core.dtypes.astype import astype_nansafe
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from pandas.core.dtypes.common import (
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ensure_object,
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is_bool_dtype,
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is_categorical_dtype,
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is_dict_like,
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is_dtype_equal,
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is_extension_array_dtype,
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is_integer,
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is_integer_dtype,
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is_list_like,
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is_object_dtype,
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is_scalar,
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is_string_dtype,
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pandas_dtype,
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)
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from pandas.core.dtypes.dtypes import CategoricalDtype
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from pandas.core.dtypes.missing import isna
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from pandas.core import algorithms
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from pandas.core.arrays import Categorical
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from pandas.core.indexes.api import (
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Index,
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MultiIndex,
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ensure_index_from_sequences,
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)
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from pandas.core.series import Series
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from pandas.core.tools import datetimes as tools
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from pandas.io.date_converters import generic_parser
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if TYPE_CHECKING:
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from pandas import DataFrame
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class ParserBase:
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class BadLineHandleMethod(Enum):
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ERROR = 0
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WARN = 1
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SKIP = 2
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_implicit_index: bool = False
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_first_chunk: bool
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def __init__(self, kwds) -> None:
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self.names = kwds.get("names")
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self.orig_names: list | None = None
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self.prefix = kwds.pop("prefix", None)
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self.index_col = kwds.get("index_col", None)
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self.unnamed_cols: set = set()
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self.index_names: Sequence[Hashable] | None = None
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self.col_names = None
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self.parse_dates = _validate_parse_dates_arg(kwds.pop("parse_dates", False))
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self._parse_date_cols: Iterable = []
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self.date_parser = kwds.pop("date_parser", None)
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self.dayfirst = kwds.pop("dayfirst", False)
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self.keep_date_col = kwds.pop("keep_date_col", False)
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self.na_values = kwds.get("na_values")
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self.na_fvalues = kwds.get("na_fvalues")
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self.na_filter = kwds.get("na_filter", False)
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self.keep_default_na = kwds.get("keep_default_na", True)
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self.dtype = copy(kwds.get("dtype", None))
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self.converters = kwds.get("converters")
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self.true_values = kwds.get("true_values")
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self.false_values = kwds.get("false_values")
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self.mangle_dupe_cols = kwds.get("mangle_dupe_cols", True)
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self.infer_datetime_format = kwds.pop("infer_datetime_format", False)
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self.cache_dates = kwds.pop("cache_dates", True)
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self._date_conv = _make_date_converter(
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date_parser=self.date_parser,
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dayfirst=self.dayfirst,
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infer_datetime_format=self.infer_datetime_format,
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cache_dates=self.cache_dates,
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)
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# validate header options for mi
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self.header = kwds.get("header")
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if is_list_like(self.header, allow_sets=False):
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if kwds.get("usecols"):
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raise ValueError(
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"cannot specify usecols when specifying a multi-index header"
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)
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if kwds.get("names"):
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raise ValueError(
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"cannot specify names when specifying a multi-index header"
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)
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# validate index_col that only contains integers
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if self.index_col is not None:
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if not (
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is_list_like(self.index_col, allow_sets=False)
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and all(map(is_integer, self.index_col))
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or is_integer(self.index_col)
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):
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raise ValueError(
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"index_col must only contain row numbers "
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"when specifying a multi-index header"
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)
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elif self.header is not None and self.prefix is not None:
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# GH 27394
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raise ValueError(
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"Argument prefix must be None if argument header is not None"
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)
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self._name_processed = False
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self._first_chunk = True
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self.usecols, self.usecols_dtype = self._validate_usecols_arg(kwds["usecols"])
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# Fallback to error to pass a sketchy test(test_override_set_noconvert_columns)
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# Normally, this arg would get pre-processed earlier on
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self.on_bad_lines = kwds.get("on_bad_lines", self.BadLineHandleMethod.ERROR)
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def _validate_parse_dates_presence(self, columns: Sequence[Hashable]) -> Iterable:
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"""
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Check if parse_dates are in columns.
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If user has provided names for parse_dates, check if those columns
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are available.
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Parameters
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----------
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columns : list
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List of names of the dataframe.
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Returns
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-------
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The names of the columns which will get parsed later if a dict or list
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is given as specification.
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Raises
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------
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ValueError
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If column to parse_date is not in dataframe.
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"""
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cols_needed: Iterable
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if is_dict_like(self.parse_dates):
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cols_needed = itertools.chain(*self.parse_dates.values())
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elif is_list_like(self.parse_dates):
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# a column in parse_dates could be represented
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# ColReference = Union[int, str]
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# DateGroups = List[ColReference]
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# ParseDates = Union[DateGroups, List[DateGroups],
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# Dict[ColReference, DateGroups]]
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cols_needed = itertools.chain.from_iterable(
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col if is_list_like(col) and not isinstance(col, tuple) else [col]
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for col in self.parse_dates
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)
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else:
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cols_needed = []
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cols_needed = list(cols_needed)
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# get only columns that are references using names (str), not by index
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missing_cols = ", ".join(
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sorted(
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{
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col
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for col in cols_needed
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if isinstance(col, str) and col not in columns
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}
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)
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)
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if missing_cols:
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raise ValueError(
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f"Missing column provided to 'parse_dates': '{missing_cols}'"
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)
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# Convert positions to actual column names
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return [
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col if (isinstance(col, str) or col in columns) else columns[col]
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for col in cols_needed
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]
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def close(self) -> None:
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pass
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@final
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@property
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def _has_complex_date_col(self) -> bool:
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return isinstance(self.parse_dates, dict) or (
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isinstance(self.parse_dates, list)
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and len(self.parse_dates) > 0
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and isinstance(self.parse_dates[0], list)
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)
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@final
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def _should_parse_dates(self, i: int) -> bool:
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if isinstance(self.parse_dates, bool):
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return self.parse_dates
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else:
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if self.index_names is not None:
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name = self.index_names[i]
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else:
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name = None
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j = i if self.index_col is None else self.index_col[i]
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if is_scalar(self.parse_dates):
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return (j == self.parse_dates) or (
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name is not None and name == self.parse_dates
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)
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else:
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return (j in self.parse_dates) or (
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name is not None and name in self.parse_dates
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)
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@final
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def _extract_multi_indexer_columns(
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self,
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header,
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index_names: list | None,
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passed_names: bool = False,
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):
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"""
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Extract and return the names, index_names, col_names if the column
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names are a MultiIndex.
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Parameters
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----------
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header: list of lists
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The header rows
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index_names: list, optional
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The names of the future index
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passed_names: bool, default False
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A flag specifying if names where passed
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"""
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if len(header) < 2:
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return header[0], index_names, None, passed_names
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# the names are the tuples of the header that are not the index cols
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# 0 is the name of the index, assuming index_col is a list of column
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# numbers
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ic = self.index_col
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if ic is None:
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ic = []
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if not isinstance(ic, (list, tuple, np.ndarray)):
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ic = [ic]
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sic = set(ic)
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# clean the index_names
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index_names = header.pop(-1)
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index_names, _, _ = self._clean_index_names(index_names, self.index_col)
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# extract the columns
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field_count = len(header[0])
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# check if header lengths are equal
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if not all(len(header_iter) == field_count for header_iter in header[1:]):
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raise ParserError("Header rows must have an equal number of columns.")
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def extract(r):
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return tuple(r[i] for i in range(field_count) if i not in sic)
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columns = list(zip(*(extract(r) for r in header)))
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names = columns.copy()
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for single_ic in sorted(ic):
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names.insert(single_ic, single_ic)
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# Clean the column names (if we have an index_col).
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if len(ic):
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col_names = [
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r[ic[0]]
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if ((r[ic[0]] is not None) and r[ic[0]] not in self.unnamed_cols)
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else None
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for r in header
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]
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else:
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col_names = [None] * len(header)
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passed_names = True
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return names, index_names, col_names, passed_names
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@final
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def _maybe_dedup_names(self, names: Sequence[Hashable]) -> Sequence[Hashable]:
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# see gh-7160 and gh-9424: this helps to provide
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# immediate alleviation of the duplicate names
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# issue and appears to be satisfactory to users,
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# but ultimately, not needing to butcher the names
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# would be nice!
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if self.mangle_dupe_cols:
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names = list(names) # so we can index
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counts: DefaultDict[Hashable, int] = defaultdict(int)
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is_potential_mi = _is_potential_multi_index(names, self.index_col)
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for i, col in enumerate(names):
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cur_count = counts[col]
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while cur_count > 0:
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counts[col] = cur_count + 1
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if is_potential_mi:
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# for mypy
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assert isinstance(col, tuple)
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col = col[:-1] + (f"{col[-1]}.{cur_count}",)
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else:
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col = f"{col}.{cur_count}"
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cur_count = counts[col]
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names[i] = col
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counts[col] = cur_count + 1
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return names
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@final
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def _maybe_make_multi_index_columns(
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self,
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columns: Sequence[Hashable],
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col_names: Sequence[Hashable] | None = None,
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) -> Sequence[Hashable] | MultiIndex:
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# possibly create a column mi here
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if _is_potential_multi_index(columns):
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list_columns = cast(List[Tuple], columns)
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return MultiIndex.from_tuples(list_columns, names=col_names)
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return columns
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@final
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def _make_index(
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self, data, alldata, columns, indexnamerow: list[Scalar] | None = None
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) -> tuple[Index | None, Sequence[Hashable] | MultiIndex]:
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index: Index | None
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if not is_index_col(self.index_col) or not self.index_col:
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index = None
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elif not self._has_complex_date_col:
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simple_index = self._get_simple_index(alldata, columns)
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index = self._agg_index(simple_index)
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elif self._has_complex_date_col:
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if not self._name_processed:
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(self.index_names, _, self.index_col) = self._clean_index_names(
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list(columns), self.index_col
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)
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self._name_processed = True
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date_index = self._get_complex_date_index(data, columns)
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index = self._agg_index(date_index, try_parse_dates=False)
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# add names for the index
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if indexnamerow:
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coffset = len(indexnamerow) - len(columns)
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assert index is not None
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index = index.set_names(indexnamerow[:coffset])
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# maybe create a mi on the columns
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columns = self._maybe_make_multi_index_columns(columns, self.col_names)
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return index, columns
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@final
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def _get_simple_index(self, data, columns):
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def ix(col):
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if not isinstance(col, str):
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return col
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raise ValueError(f"Index {col} invalid")
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to_remove = []
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index = []
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for idx in self.index_col:
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i = ix(idx)
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to_remove.append(i)
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index.append(data[i])
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# remove index items from content and columns, don't pop in
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# loop
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for i in sorted(to_remove, reverse=True):
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data.pop(i)
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if not self._implicit_index:
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columns.pop(i)
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return index
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|
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@final
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def _get_complex_date_index(self, data, col_names):
|
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def _get_name(icol):
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if isinstance(icol, str):
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return icol
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if col_names is None:
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raise ValueError(f"Must supply column order to use {icol!s} as index")
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for i, c in enumerate(col_names):
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if i == icol:
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return c
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to_remove = []
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index = []
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for idx in self.index_col:
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name = _get_name(idx)
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to_remove.append(name)
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index.append(data[name])
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# remove index items from content and columns, don't pop in
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# loop
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for c in sorted(to_remove, reverse=True):
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data.pop(c)
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col_names.remove(c)
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return index
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|
|
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def _clean_mapping(self, mapping):
|
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"""converts col numbers to names"""
|
|
if not isinstance(mapping, dict):
|
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return mapping
|
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clean = {}
|
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# for mypy
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assert self.orig_names is not None
|
|
|
|
for col, v in mapping.items():
|
|
if isinstance(col, int) and col not in self.orig_names:
|
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col = self.orig_names[col]
|
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clean[col] = v
|
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if isinstance(mapping, defaultdict):
|
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remaining_cols = set(self.orig_names) - set(clean.keys())
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clean.update({col: mapping[col] for col in remaining_cols})
|
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return clean
|
|
|
|
@final
|
|
def _agg_index(self, index, try_parse_dates: bool = True) -> Index:
|
|
arrays = []
|
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converters = self._clean_mapping(self.converters)
|
|
|
|
for i, arr in enumerate(index):
|
|
|
|
if try_parse_dates and self._should_parse_dates(i):
|
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arr = self._date_conv(arr)
|
|
|
|
if self.na_filter:
|
|
col_na_values = self.na_values
|
|
col_na_fvalues = self.na_fvalues
|
|
else:
|
|
col_na_values = set()
|
|
col_na_fvalues = set()
|
|
|
|
if isinstance(self.na_values, dict):
|
|
assert self.index_names is not None
|
|
col_name = self.index_names[i]
|
|
if col_name is not None:
|
|
col_na_values, col_na_fvalues = _get_na_values(
|
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col_name, self.na_values, self.na_fvalues, self.keep_default_na
|
|
)
|
|
|
|
clean_dtypes = self._clean_mapping(self.dtype)
|
|
|
|
cast_type = None
|
|
index_converter = False
|
|
if self.index_names is not None:
|
|
if isinstance(clean_dtypes, dict):
|
|
cast_type = clean_dtypes.get(self.index_names[i], None)
|
|
|
|
if isinstance(converters, dict):
|
|
index_converter = converters.get(self.index_names[i]) is not None
|
|
|
|
try_num_bool = not (
|
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cast_type and is_string_dtype(cast_type) or index_converter
|
|
)
|
|
|
|
arr, _ = self._infer_types(
|
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arr, col_na_values | col_na_fvalues, try_num_bool
|
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)
|
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arrays.append(arr)
|
|
|
|
names = self.index_names
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index = ensure_index_from_sequences(arrays, names)
|
|
|
|
return index
|
|
|
|
@final
|
|
def _convert_to_ndarrays(
|
|
self,
|
|
dct: Mapping,
|
|
na_values,
|
|
na_fvalues,
|
|
verbose: bool = False,
|
|
converters=None,
|
|
dtypes=None,
|
|
):
|
|
result = {}
|
|
for c, values in dct.items():
|
|
conv_f = None if converters is None else converters.get(c, None)
|
|
if isinstance(dtypes, dict):
|
|
cast_type = dtypes.get(c, None)
|
|
else:
|
|
# single dtype or None
|
|
cast_type = dtypes
|
|
|
|
if self.na_filter:
|
|
col_na_values, col_na_fvalues = _get_na_values(
|
|
c, na_values, na_fvalues, self.keep_default_na
|
|
)
|
|
else:
|
|
col_na_values, col_na_fvalues = set(), set()
|
|
|
|
if c in self._parse_date_cols:
|
|
# GH#26203 Do not convert columns which get converted to dates
|
|
# but replace nans to ensure to_datetime works
|
|
mask = algorithms.isin(values, set(col_na_values) | col_na_fvalues)
|
|
np.putmask(values, mask, np.nan)
|
|
result[c] = values
|
|
continue
|
|
|
|
if conv_f is not None:
|
|
# conv_f applied to data before inference
|
|
if cast_type is not None:
|
|
warnings.warn(
|
|
(
|
|
"Both a converter and dtype were specified "
|
|
f"for column {c} - only the converter will be used."
|
|
),
|
|
ParserWarning,
|
|
stacklevel=find_stack_level(),
|
|
)
|
|
|
|
try:
|
|
values = lib.map_infer(values, conv_f)
|
|
except ValueError:
|
|
# error: Argument 2 to "isin" has incompatible type "List[Any]";
|
|
# expected "Union[Union[ExtensionArray, ndarray], Index, Series]"
|
|
mask = algorithms.isin(
|
|
values, list(na_values) # type: ignore[arg-type]
|
|
).view(np.uint8)
|
|
values = lib.map_infer_mask(values, conv_f, mask)
|
|
|
|
cvals, na_count = self._infer_types(
|
|
values, set(col_na_values) | col_na_fvalues, try_num_bool=False
|
|
)
|
|
else:
|
|
is_ea = is_extension_array_dtype(cast_type)
|
|
is_str_or_ea_dtype = is_ea or is_string_dtype(cast_type)
|
|
# skip inference if specified dtype is object
|
|
# or casting to an EA
|
|
try_num_bool = not (cast_type and is_str_or_ea_dtype)
|
|
|
|
# general type inference and conversion
|
|
cvals, na_count = self._infer_types(
|
|
values, set(col_na_values) | col_na_fvalues, try_num_bool
|
|
)
|
|
|
|
# type specified in dtype param or cast_type is an EA
|
|
if cast_type and (
|
|
not is_dtype_equal(cvals, cast_type)
|
|
or is_extension_array_dtype(cast_type)
|
|
):
|
|
if not is_ea and na_count > 0:
|
|
try:
|
|
if is_bool_dtype(cast_type):
|
|
raise ValueError(
|
|
f"Bool column has NA values in column {c}"
|
|
)
|
|
except (AttributeError, TypeError):
|
|
# invalid input to is_bool_dtype
|
|
pass
|
|
cast_type = pandas_dtype(cast_type)
|
|
cvals = self._cast_types(cvals, cast_type, c)
|
|
|
|
result[c] = cvals
|
|
if verbose and na_count:
|
|
print(f"Filled {na_count} NA values in column {c!s}")
|
|
return result
|
|
|
|
@final
|
|
def _set_noconvert_dtype_columns(
|
|
self, col_indices: list[int], names: Sequence[Hashable]
|
|
) -> set[int]:
|
|
"""
|
|
Set the columns that should not undergo dtype conversions.
|
|
|
|
Currently, any column that is involved with date parsing will not
|
|
undergo such conversions. If usecols is specified, the positions of the columns
|
|
not to cast is relative to the usecols not to all columns.
|
|
|
|
Parameters
|
|
----------
|
|
col_indices: The indices specifying order and positions of the columns
|
|
names: The column names which order is corresponding with the order
|
|
of col_indices
|
|
|
|
Returns
|
|
-------
|
|
A set of integers containing the positions of the columns not to convert.
|
|
"""
|
|
usecols: list[int] | list[str] | None
|
|
noconvert_columns = set()
|
|
if self.usecols_dtype == "integer":
|
|
# A set of integers will be converted to a list in
|
|
# the correct order every single time.
|
|
usecols = sorted(self.usecols)
|
|
elif callable(self.usecols) or self.usecols_dtype not in ("empty", None):
|
|
# The names attribute should have the correct columns
|
|
# in the proper order for indexing with parse_dates.
|
|
usecols = col_indices
|
|
else:
|
|
# Usecols is empty.
|
|
usecols = None
|
|
|
|
def _set(x) -> int:
|
|
if usecols is not None and is_integer(x):
|
|
x = usecols[x]
|
|
|
|
if not is_integer(x):
|
|
x = col_indices[names.index(x)]
|
|
|
|
return x
|
|
|
|
if isinstance(self.parse_dates, list):
|
|
for val in self.parse_dates:
|
|
if isinstance(val, list):
|
|
for k in val:
|
|
noconvert_columns.add(_set(k))
|
|
else:
|
|
noconvert_columns.add(_set(val))
|
|
|
|
elif isinstance(self.parse_dates, dict):
|
|
for val in self.parse_dates.values():
|
|
if isinstance(val, list):
|
|
for k in val:
|
|
noconvert_columns.add(_set(k))
|
|
else:
|
|
noconvert_columns.add(_set(val))
|
|
|
|
elif self.parse_dates:
|
|
if isinstance(self.index_col, list):
|
|
for k in self.index_col:
|
|
noconvert_columns.add(_set(k))
|
|
elif self.index_col is not None:
|
|
noconvert_columns.add(_set(self.index_col))
|
|
|
|
return noconvert_columns
|
|
|
|
def _infer_types(self, values, na_values, try_num_bool=True):
|
|
"""
|
|
Infer types of values, possibly casting
|
|
|
|
Parameters
|
|
----------
|
|
values : ndarray
|
|
na_values : set
|
|
try_num_bool : bool, default try
|
|
try to cast values to numeric (first preference) or boolean
|
|
|
|
Returns
|
|
-------
|
|
converted : ndarray
|
|
na_count : int
|
|
"""
|
|
na_count = 0
|
|
if issubclass(values.dtype.type, (np.number, np.bool_)):
|
|
# If our array has numeric dtype, we don't have to check for strings in isin
|
|
na_values = np.array([val for val in na_values if not isinstance(val, str)])
|
|
mask = algorithms.isin(values, na_values)
|
|
na_count = mask.astype("uint8", copy=False).sum()
|
|
if na_count > 0:
|
|
if is_integer_dtype(values):
|
|
values = values.astype(np.float64)
|
|
np.putmask(values, mask, np.nan)
|
|
return values, na_count
|
|
|
|
if try_num_bool and is_object_dtype(values.dtype):
|
|
# exclude e.g DatetimeIndex here
|
|
try:
|
|
result, _ = lib.maybe_convert_numeric(values, na_values, False)
|
|
except (ValueError, TypeError):
|
|
# e.g. encountering datetime string gets ValueError
|
|
# TypeError can be raised in floatify
|
|
result = values
|
|
na_count = parsers.sanitize_objects(result, na_values)
|
|
else:
|
|
na_count = isna(result).sum()
|
|
else:
|
|
result = values
|
|
if values.dtype == np.object_:
|
|
na_count = parsers.sanitize_objects(values, na_values)
|
|
|
|
if result.dtype == np.object_ and try_num_bool:
|
|
result, _ = libops.maybe_convert_bool(
|
|
np.asarray(values),
|
|
true_values=self.true_values,
|
|
false_values=self.false_values,
|
|
)
|
|
|
|
return result, na_count
|
|
|
|
def _cast_types(self, values, cast_type, column):
|
|
"""
|
|
Cast values to specified type
|
|
|
|
Parameters
|
|
----------
|
|
values : ndarray
|
|
cast_type : string or np.dtype
|
|
dtype to cast values to
|
|
column : string
|
|
column name - used only for error reporting
|
|
|
|
Returns
|
|
-------
|
|
converted : ndarray
|
|
"""
|
|
if is_categorical_dtype(cast_type):
|
|
known_cats = (
|
|
isinstance(cast_type, CategoricalDtype)
|
|
and cast_type.categories is not None
|
|
)
|
|
|
|
if not is_object_dtype(values) and not known_cats:
|
|
# TODO: this is for consistency with
|
|
# c-parser which parses all categories
|
|
# as strings
|
|
|
|
values = astype_nansafe(values, np.dtype(str))
|
|
|
|
cats = Index(values).unique().dropna()
|
|
values = Categorical._from_inferred_categories(
|
|
cats, cats.get_indexer(values), cast_type, true_values=self.true_values
|
|
)
|
|
|
|
# use the EA's implementation of casting
|
|
elif is_extension_array_dtype(cast_type):
|
|
# ensure cast_type is an actual dtype and not a string
|
|
cast_type = pandas_dtype(cast_type)
|
|
array_type = cast_type.construct_array_type()
|
|
try:
|
|
if is_bool_dtype(cast_type):
|
|
return array_type._from_sequence_of_strings(
|
|
values,
|
|
dtype=cast_type,
|
|
true_values=self.true_values,
|
|
false_values=self.false_values,
|
|
)
|
|
else:
|
|
return array_type._from_sequence_of_strings(values, dtype=cast_type)
|
|
except NotImplementedError as err:
|
|
raise NotImplementedError(
|
|
f"Extension Array: {array_type} must implement "
|
|
"_from_sequence_of_strings in order to be used in parser methods"
|
|
) from err
|
|
|
|
else:
|
|
try:
|
|
values = astype_nansafe(values, cast_type, copy=True, skipna=True)
|
|
except ValueError as err:
|
|
raise ValueError(
|
|
f"Unable to convert column {column} to type {cast_type}"
|
|
) from err
|
|
return values
|
|
|
|
@overload
|
|
def _do_date_conversions(
|
|
self,
|
|
names: Index,
|
|
data: DataFrame,
|
|
) -> tuple[Sequence[Hashable] | Index, DataFrame]:
|
|
...
|
|
|
|
@overload
|
|
def _do_date_conversions(
|
|
self,
|
|
names: Sequence[Hashable],
|
|
data: Mapping[Hashable, ArrayLike],
|
|
) -> tuple[Sequence[Hashable], Mapping[Hashable, ArrayLike]]:
|
|
...
|
|
|
|
def _do_date_conversions(
|
|
self,
|
|
names: Sequence[Hashable] | Index,
|
|
data: Mapping[Hashable, ArrayLike] | DataFrame,
|
|
) -> tuple[Sequence[Hashable] | Index, Mapping[Hashable, ArrayLike] | DataFrame]:
|
|
# returns data, columns
|
|
|
|
if self.parse_dates is not None:
|
|
data, names = _process_date_conversion(
|
|
data,
|
|
self._date_conv,
|
|
self.parse_dates,
|
|
self.index_col,
|
|
self.index_names,
|
|
names,
|
|
keep_date_col=self.keep_date_col,
|
|
)
|
|
|
|
return names, data
|
|
|
|
def _check_data_length(
|
|
self,
|
|
columns: Sequence[Hashable],
|
|
data: Sequence[ArrayLike],
|
|
) -> None:
|
|
"""Checks if length of data is equal to length of column names.
|
|
|
|
One set of trailing commas is allowed. self.index_col not False
|
|
results in a ParserError previously when lengths do not match.
|
|
|
|
Parameters
|
|
----------
|
|
columns: list of column names
|
|
data: list of array-likes containing the data column-wise.
|
|
"""
|
|
if not self.index_col and len(columns) != len(data) and columns:
|
|
empty_str = is_object_dtype(data[-1]) and data[-1] == ""
|
|
# error: No overload variant of "__ror__" of "ndarray" matches
|
|
# argument type "ExtensionArray"
|
|
empty_str_or_na = empty_str | isna(data[-1]) # type: ignore[operator]
|
|
if len(columns) == len(data) - 1 and np.all(empty_str_or_na):
|
|
return
|
|
warnings.warn(
|
|
"Length of header or names does not match length of data. This leads "
|
|
"to a loss of data with index_col=False.",
|
|
ParserWarning,
|
|
stacklevel=find_stack_level(),
|
|
)
|
|
|
|
@overload
|
|
def _evaluate_usecols(
|
|
self,
|
|
usecols: set[int] | Callable[[Hashable], object],
|
|
names: Sequence[Hashable],
|
|
) -> set[int]:
|
|
...
|
|
|
|
@overload
|
|
def _evaluate_usecols(
|
|
self, usecols: set[str], names: Sequence[Hashable]
|
|
) -> set[str]:
|
|
...
|
|
|
|
def _evaluate_usecols(
|
|
self,
|
|
usecols: Callable[[Hashable], object] | set[str] | set[int],
|
|
names: Sequence[Hashable],
|
|
) -> set[str] | set[int]:
|
|
"""
|
|
Check whether or not the 'usecols' parameter
|
|
is a callable. If so, enumerates the 'names'
|
|
parameter and returns a set of indices for
|
|
each entry in 'names' that evaluates to True.
|
|
If not a callable, returns 'usecols'.
|
|
"""
|
|
if callable(usecols):
|
|
return {i for i, name in enumerate(names) if usecols(name)}
|
|
return usecols
|
|
|
|
def _validate_usecols_names(self, usecols, names):
|
|
"""
|
|
Validates that all usecols are present in a given
|
|
list of names. If not, raise a ValueError that
|
|
shows what usecols are missing.
|
|
|
|
Parameters
|
|
----------
|
|
usecols : iterable of usecols
|
|
The columns to validate are present in names.
|
|
names : iterable of names
|
|
The column names to check against.
|
|
|
|
Returns
|
|
-------
|
|
usecols : iterable of usecols
|
|
The `usecols` parameter if the validation succeeds.
|
|
|
|
Raises
|
|
------
|
|
ValueError : Columns were missing. Error message will list them.
|
|
"""
|
|
missing = [c for c in usecols if c not in names]
|
|
if len(missing) > 0:
|
|
raise ValueError(
|
|
f"Usecols do not match columns, columns expected but not found: "
|
|
f"{missing}"
|
|
)
|
|
|
|
return usecols
|
|
|
|
def _validate_usecols_arg(self, usecols):
|
|
"""
|
|
Validate the 'usecols' parameter.
|
|
|
|
Checks whether or not the 'usecols' parameter contains all integers
|
|
(column selection by index), strings (column by name) or is a callable.
|
|
Raises a ValueError if that is not the case.
|
|
|
|
Parameters
|
|
----------
|
|
usecols : list-like, callable, or None
|
|
List of columns to use when parsing or a callable that can be used
|
|
to filter a list of table columns.
|
|
|
|
Returns
|
|
-------
|
|
usecols_tuple : tuple
|
|
A tuple of (verified_usecols, usecols_dtype).
|
|
|
|
'verified_usecols' is either a set if an array-like is passed in or
|
|
'usecols' if a callable or None is passed in.
|
|
|
|
'usecols_dtype` is the inferred dtype of 'usecols' if an array-like
|
|
is passed in or None if a callable or None is passed in.
|
|
"""
|
|
msg = (
|
|
"'usecols' must either be list-like of all strings, all unicode, "
|
|
"all integers or a callable."
|
|
)
|
|
if usecols is not None:
|
|
if callable(usecols):
|
|
return usecols, None
|
|
|
|
if not is_list_like(usecols):
|
|
# see gh-20529
|
|
#
|
|
# Ensure it is iterable container but not string.
|
|
raise ValueError(msg)
|
|
|
|
usecols_dtype = lib.infer_dtype(usecols, skipna=False)
|
|
|
|
if usecols_dtype not in ("empty", "integer", "string"):
|
|
raise ValueError(msg)
|
|
|
|
usecols = set(usecols)
|
|
|
|
return usecols, usecols_dtype
|
|
return usecols, None
|
|
|
|
def _clean_index_names(self, columns, index_col):
|
|
if not is_index_col(index_col):
|
|
return None, columns, index_col
|
|
|
|
columns = list(columns)
|
|
|
|
# In case of no rows and multiindex columns we have to set index_names to
|
|
# list of Nones GH#38292
|
|
if not columns:
|
|
return [None] * len(index_col), columns, index_col
|
|
|
|
cp_cols = list(columns)
|
|
index_names: list[str | int | None] = []
|
|
|
|
# don't mutate
|
|
index_col = list(index_col)
|
|
|
|
for i, c in enumerate(index_col):
|
|
if isinstance(c, str):
|
|
index_names.append(c)
|
|
for j, name in enumerate(cp_cols):
|
|
if name == c:
|
|
index_col[i] = j
|
|
columns.remove(name)
|
|
break
|
|
else:
|
|
name = cp_cols[c]
|
|
columns.remove(name)
|
|
index_names.append(name)
|
|
|
|
# Only clean index names that were placeholders.
|
|
for i, name in enumerate(index_names):
|
|
if isinstance(name, str) and name in self.unnamed_cols:
|
|
index_names[i] = None
|
|
|
|
return index_names, columns, index_col
|
|
|
|
def _get_empty_meta(
|
|
self, columns, index_col, index_names, dtype: DtypeArg | None = None
|
|
):
|
|
columns = list(columns)
|
|
|
|
# Convert `dtype` to a defaultdict of some kind.
|
|
# This will enable us to write `dtype[col_name]`
|
|
# without worrying about KeyError issues later on.
|
|
dtype_dict: defaultdict[Hashable, Any]
|
|
if not is_dict_like(dtype):
|
|
# if dtype == None, default will be object.
|
|
default_dtype = dtype or object
|
|
dtype_dict = defaultdict(lambda: default_dtype)
|
|
else:
|
|
dtype = cast(dict, dtype)
|
|
dtype_dict = defaultdict(
|
|
lambda: object,
|
|
{columns[k] if is_integer(k) else k: v for k, v in dtype.items()},
|
|
)
|
|
|
|
# Even though we have no data, the "index" of the empty DataFrame
|
|
# could for example still be an empty MultiIndex. Thus, we need to
|
|
# check whether we have any index columns specified, via either:
|
|
#
|
|
# 1) index_col (column indices)
|
|
# 2) index_names (column names)
|
|
#
|
|
# Both must be non-null to ensure a successful construction. Otherwise,
|
|
# we have to create a generic empty Index.
|
|
if (index_col is None or index_col is False) or index_names is None:
|
|
index = Index([])
|
|
else:
|
|
data = [Series([], dtype=dtype_dict[name]) for name in index_names]
|
|
index = ensure_index_from_sequences(data, names=index_names)
|
|
index_col.sort()
|
|
|
|
for i, n in enumerate(index_col):
|
|
columns.pop(n - i)
|
|
|
|
col_dict = {
|
|
col_name: Series([], dtype=dtype_dict[col_name]) for col_name in columns
|
|
}
|
|
|
|
return index, columns, col_dict
|
|
|
|
|
|
def _make_date_converter(
|
|
date_parser=None, dayfirst=False, infer_datetime_format=False, cache_dates=True
|
|
):
|
|
def converter(*date_cols):
|
|
if date_parser is None:
|
|
strs = parsing.concat_date_cols(date_cols)
|
|
|
|
try:
|
|
return tools.to_datetime(
|
|
ensure_object(strs),
|
|
utc=None,
|
|
dayfirst=dayfirst,
|
|
errors="ignore",
|
|
infer_datetime_format=infer_datetime_format,
|
|
cache=cache_dates,
|
|
).to_numpy()
|
|
|
|
except ValueError:
|
|
return tools.to_datetime(
|
|
parsing.try_parse_dates(strs, dayfirst=dayfirst), cache=cache_dates
|
|
)
|
|
else:
|
|
try:
|
|
result = tools.to_datetime(
|
|
date_parser(*date_cols), errors="ignore", cache=cache_dates
|
|
)
|
|
if isinstance(result, datetime.datetime):
|
|
raise Exception("scalar parser")
|
|
return result
|
|
except Exception:
|
|
try:
|
|
return tools.to_datetime(
|
|
parsing.try_parse_dates(
|
|
parsing.concat_date_cols(date_cols),
|
|
parser=date_parser,
|
|
dayfirst=dayfirst,
|
|
),
|
|
errors="ignore",
|
|
)
|
|
except Exception:
|
|
return generic_parser(date_parser, *date_cols)
|
|
|
|
return converter
|
|
|
|
|
|
parser_defaults = {
|
|
"delimiter": None,
|
|
"escapechar": None,
|
|
"quotechar": '"',
|
|
"quoting": csv.QUOTE_MINIMAL,
|
|
"doublequote": True,
|
|
"skipinitialspace": False,
|
|
"lineterminator": None,
|
|
"header": "infer",
|
|
"index_col": None,
|
|
"names": None,
|
|
"prefix": None,
|
|
"skiprows": None,
|
|
"skipfooter": 0,
|
|
"nrows": None,
|
|
"na_values": None,
|
|
"keep_default_na": True,
|
|
"true_values": None,
|
|
"false_values": None,
|
|
"converters": None,
|
|
"dtype": None,
|
|
"cache_dates": True,
|
|
"thousands": None,
|
|
"comment": None,
|
|
"decimal": ".",
|
|
# 'engine': 'c',
|
|
"parse_dates": False,
|
|
"keep_date_col": False,
|
|
"dayfirst": False,
|
|
"date_parser": None,
|
|
"usecols": None,
|
|
# 'iterator': False,
|
|
"chunksize": None,
|
|
"verbose": False,
|
|
"encoding": None,
|
|
"squeeze": None,
|
|
"compression": None,
|
|
"mangle_dupe_cols": True,
|
|
"infer_datetime_format": False,
|
|
"skip_blank_lines": True,
|
|
"encoding_errors": "strict",
|
|
"on_bad_lines": ParserBase.BadLineHandleMethod.ERROR,
|
|
"error_bad_lines": None,
|
|
"warn_bad_lines": None,
|
|
}
|
|
|
|
|
|
def _process_date_conversion(
|
|
data_dict,
|
|
converter: Callable,
|
|
parse_spec,
|
|
index_col,
|
|
index_names,
|
|
columns,
|
|
keep_date_col: bool = False,
|
|
):
|
|
def _isindex(colspec):
|
|
return (isinstance(index_col, list) and colspec in index_col) or (
|
|
isinstance(index_names, list) and colspec in index_names
|
|
)
|
|
|
|
new_cols = []
|
|
new_data = {}
|
|
|
|
orig_names = columns
|
|
columns = list(columns)
|
|
|
|
date_cols = set()
|
|
|
|
if parse_spec is None or isinstance(parse_spec, bool):
|
|
return data_dict, columns
|
|
|
|
if isinstance(parse_spec, list):
|
|
# list of column lists
|
|
for colspec in parse_spec:
|
|
if is_scalar(colspec) or isinstance(colspec, tuple):
|
|
if isinstance(colspec, int) and colspec not in data_dict:
|
|
colspec = orig_names[colspec]
|
|
if _isindex(colspec):
|
|
continue
|
|
# Pyarrow engine returns Series which we need to convert to
|
|
# numpy array before converter, its a no-op for other parsers
|
|
data_dict[colspec] = converter(np.asarray(data_dict[colspec]))
|
|
else:
|
|
new_name, col, old_names = _try_convert_dates(
|
|
converter, colspec, data_dict, orig_names
|
|
)
|
|
if new_name in data_dict:
|
|
raise ValueError(f"New date column already in dict {new_name}")
|
|
new_data[new_name] = col
|
|
new_cols.append(new_name)
|
|
date_cols.update(old_names)
|
|
|
|
elif isinstance(parse_spec, dict):
|
|
# dict of new name to column list
|
|
for new_name, colspec in parse_spec.items():
|
|
if new_name in data_dict:
|
|
raise ValueError(f"Date column {new_name} already in dict")
|
|
|
|
_, col, old_names = _try_convert_dates(
|
|
converter, colspec, data_dict, orig_names
|
|
)
|
|
|
|
new_data[new_name] = col
|
|
|
|
# If original column can be converted to date we keep the converted values
|
|
# This can only happen if values are from single column
|
|
if len(colspec) == 1:
|
|
new_data[colspec[0]] = col
|
|
|
|
new_cols.append(new_name)
|
|
date_cols.update(old_names)
|
|
|
|
data_dict.update(new_data)
|
|
new_cols.extend(columns)
|
|
|
|
if not keep_date_col:
|
|
for c in list(date_cols):
|
|
data_dict.pop(c)
|
|
new_cols.remove(c)
|
|
|
|
return data_dict, new_cols
|
|
|
|
|
|
def _try_convert_dates(parser: Callable, colspec, data_dict, columns):
|
|
colset = set(columns)
|
|
colnames = []
|
|
|
|
for c in colspec:
|
|
if c in colset:
|
|
colnames.append(c)
|
|
elif isinstance(c, int) and c not in columns:
|
|
colnames.append(columns[c])
|
|
else:
|
|
colnames.append(c)
|
|
|
|
new_name: tuple | str
|
|
if all(isinstance(x, tuple) for x in colnames):
|
|
new_name = tuple(map("_".join, zip(*colnames)))
|
|
else:
|
|
new_name = "_".join([str(x) for x in colnames])
|
|
to_parse = [np.asarray(data_dict[c]) for c in colnames if c in data_dict]
|
|
|
|
new_col = parser(*to_parse)
|
|
return new_name, new_col, colnames
|
|
|
|
|
|
def _get_na_values(col, na_values, na_fvalues, keep_default_na):
|
|
"""
|
|
Get the NaN values for a given column.
|
|
|
|
Parameters
|
|
----------
|
|
col : str
|
|
The name of the column.
|
|
na_values : array-like, dict
|
|
The object listing the NaN values as strings.
|
|
na_fvalues : array-like, dict
|
|
The object listing the NaN values as floats.
|
|
keep_default_na : bool
|
|
If `na_values` is a dict, and the column is not mapped in the
|
|
dictionary, whether to return the default NaN values or the empty set.
|
|
|
|
Returns
|
|
-------
|
|
nan_tuple : A length-two tuple composed of
|
|
|
|
1) na_values : the string NaN values for that column.
|
|
2) na_fvalues : the float NaN values for that column.
|
|
"""
|
|
if isinstance(na_values, dict):
|
|
if col in na_values:
|
|
return na_values[col], na_fvalues[col]
|
|
else:
|
|
if keep_default_na:
|
|
return STR_NA_VALUES, set()
|
|
|
|
return set(), set()
|
|
else:
|
|
return na_values, na_fvalues
|
|
|
|
|
|
def _is_potential_multi_index(
|
|
columns: Sequence[Hashable] | MultiIndex,
|
|
index_col: bool | Sequence[int] | None = None,
|
|
) -> bool:
|
|
"""
|
|
Check whether or not the `columns` parameter
|
|
could be converted into a MultiIndex.
|
|
|
|
Parameters
|
|
----------
|
|
columns : array-like
|
|
Object which may or may not be convertible into a MultiIndex
|
|
index_col : None, bool or list, optional
|
|
Column or columns to use as the (possibly hierarchical) index
|
|
|
|
Returns
|
|
-------
|
|
bool : Whether or not columns could become a MultiIndex
|
|
"""
|
|
if index_col is None or isinstance(index_col, bool):
|
|
index_col = []
|
|
|
|
return bool(
|
|
len(columns)
|
|
and not isinstance(columns, MultiIndex)
|
|
and all(isinstance(c, tuple) for c in columns if c not in list(index_col))
|
|
)
|
|
|
|
|
|
def _validate_parse_dates_arg(parse_dates):
|
|
"""
|
|
Check whether or not the 'parse_dates' parameter
|
|
is a non-boolean scalar. Raises a ValueError if
|
|
that is the case.
|
|
"""
|
|
msg = (
|
|
"Only booleans, lists, and dictionaries are accepted "
|
|
"for the 'parse_dates' parameter"
|
|
)
|
|
|
|
if parse_dates is not None:
|
|
if is_scalar(parse_dates):
|
|
if not lib.is_bool(parse_dates):
|
|
raise TypeError(msg)
|
|
|
|
elif not isinstance(parse_dates, (list, dict)):
|
|
raise TypeError(msg)
|
|
|
|
return parse_dates
|
|
|
|
|
|
def is_index_col(col) -> bool:
|
|
return col is not None and col is not False
|