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ai-content-maker/.venv/Lib/site-packages/pandas/io/parsers/python_parser.py

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first commit
2024-05-03 04:18:51 +03:00
from __future__ import annotations
from collections import (
abc,
defaultdict,
)
import csv
from io import StringIO
import re
import sys
from typing import (
IO,
TYPE_CHECKING,
DefaultDict,
Hashable,
Iterator,
List,
Literal,
Mapping,
Sequence,
cast,
)
import warnings
import numpy as np
import pandas._libs.lib as lib
from pandas._typing import (
ArrayLike,
ReadCsvBuffer,
Scalar,
)
from pandas.errors import (
EmptyDataError,
ParserError,
)
from pandas.util._exceptions import find_stack_level
from pandas.core.dtypes.common import is_integer
from pandas.core.dtypes.inference import is_dict_like
from pandas.io.parsers.base_parser import (
ParserBase,
parser_defaults,
)
if TYPE_CHECKING:
from pandas import (
Index,
MultiIndex,
)
# BOM character (byte order mark)
# This exists at the beginning of a file to indicate endianness
# of a file (stream). Unfortunately, this marker screws up parsing,
# so we need to remove it if we see it.
_BOM = "\ufeff"
class PythonParser(ParserBase):
def __init__(self, f: ReadCsvBuffer[str] | list, **kwds) -> None:
"""
Workhorse function for processing nested list into DataFrame
"""
super().__init__(kwds)
self.data: Iterator[str] | None = None
self.buf: list = []
self.pos = 0
self.line_pos = 0
self.skiprows = kwds["skiprows"]
if callable(self.skiprows):
self.skipfunc = self.skiprows
else:
self.skipfunc = lambda x: x in self.skiprows
self.skipfooter = _validate_skipfooter_arg(kwds["skipfooter"])
self.delimiter = kwds["delimiter"]
self.quotechar = kwds["quotechar"]
if isinstance(self.quotechar, str):
self.quotechar = str(self.quotechar)
self.escapechar = kwds["escapechar"]
self.doublequote = kwds["doublequote"]
self.skipinitialspace = kwds["skipinitialspace"]
self.lineterminator = kwds["lineterminator"]
self.quoting = kwds["quoting"]
self.skip_blank_lines = kwds["skip_blank_lines"]
self.names_passed = kwds["names"] or None
self.has_index_names = False
if "has_index_names" in kwds:
self.has_index_names = kwds["has_index_names"]
self.verbose = kwds["verbose"]
self.thousands = kwds["thousands"]
self.decimal = kwds["decimal"]
self.comment = kwds["comment"]
# Set self.data to something that can read lines.
if isinstance(f, list):
# read_excel: f is a list
self.data = cast(Iterator[str], f)
else:
assert hasattr(f, "readline")
self._make_reader(f)
# Get columns in two steps: infer from data, then
# infer column indices from self.usecols if it is specified.
self._col_indices: list[int] | None = None
columns: list[list[Scalar | None]]
(
columns,
self.num_original_columns,
self.unnamed_cols,
) = self._infer_columns()
# Now self.columns has the set of columns that we will process.
# The original set is stored in self.original_columns.
# error: Cannot determine type of 'index_names'
self.columns: list[Hashable]
(
self.columns,
self.index_names,
self.col_names,
_,
) = self._extract_multi_indexer_columns(
columns,
self.index_names, # type: ignore[has-type]
)
# get popped off for index
self.orig_names: list[Hashable] = list(self.columns)
# needs to be cleaned/refactored
# multiple date column thing turning into a real spaghetti factory
if not self._has_complex_date_col:
(index_names, self.orig_names, self.columns) = self._get_index_name(
self.columns
)
self._name_processed = True
if self.index_names is None:
self.index_names = index_names
if self._col_indices is None:
self._col_indices = list(range(len(self.columns)))
self._parse_date_cols = self._validate_parse_dates_presence(self.columns)
no_thousands_columns: set[int] | None = None
if self.parse_dates:
no_thousands_columns = self._set_noconvert_dtype_columns(
self._col_indices, self.columns
)
self._no_thousands_columns = no_thousands_columns
if len(self.decimal) != 1:
raise ValueError("Only length-1 decimal markers supported")
decimal = re.escape(self.decimal)
if self.thousands is None:
regex = rf"^[\-\+]?[0-9]*({decimal}[0-9]*)?([0-9]?(E|e)\-?[0-9]+)?$"
else:
thousands = re.escape(self.thousands)
regex = (
rf"^[\-\+]?([0-9]+{thousands}|[0-9])*({decimal}[0-9]*)?"
rf"([0-9]?(E|e)\-?[0-9]+)?$"
)
self.num = re.compile(regex)
def _make_reader(self, f: IO[str] | ReadCsvBuffer[str]) -> None:
sep = self.delimiter
if sep is None or len(sep) == 1:
if self.lineterminator:
raise ValueError(
"Custom line terminators not supported in python parser (yet)"
)
class MyDialect(csv.Dialect):
delimiter = self.delimiter
quotechar = self.quotechar
escapechar = self.escapechar
doublequote = self.doublequote
skipinitialspace = self.skipinitialspace
quoting = self.quoting
lineterminator = "\n"
dia = MyDialect
if sep is not None:
dia.delimiter = sep
else:
# attempt to sniff the delimiter from the first valid line,
# i.e. no comment line and not in skiprows
line = f.readline()
lines = self._check_comments([[line]])[0]
while self.skipfunc(self.pos) or not lines:
self.pos += 1
line = f.readline()
lines = self._check_comments([[line]])[0]
lines_str = cast(List[str], lines)
# since `line` was a string, lines will be a list containing
# only a single string
line = lines_str[0]
self.pos += 1
self.line_pos += 1
sniffed = csv.Sniffer().sniff(line)
dia.delimiter = sniffed.delimiter
# Note: encoding is irrelevant here
line_rdr = csv.reader(StringIO(line), dialect=dia)
self.buf.extend(list(line_rdr))
# Note: encoding is irrelevant here
reader = csv.reader(f, dialect=dia, strict=True)
else:
def _read():
line = f.readline()
pat = re.compile(sep)
yield pat.split(line.strip())
for line in f:
yield pat.split(line.strip())
reader = _read()
# error: Incompatible types in assignment (expression has type "_reader",
# variable has type "Union[IO[Any], RawIOBase, BufferedIOBase, TextIOBase,
# TextIOWrapper, mmap, None]")
self.data = reader # type: ignore[assignment]
def read(
self, rows: int | None = None
) -> tuple[
Index | None, Sequence[Hashable] | MultiIndex, Mapping[Hashable, ArrayLike]
]:
try:
content = self._get_lines(rows)
except StopIteration:
if self._first_chunk:
content = []
else:
self.close()
raise
# done with first read, next time raise StopIteration
self._first_chunk = False
columns: Sequence[Hashable] = list(self.orig_names)
if not len(content): # pragma: no cover
# DataFrame with the right metadata, even though it's length 0
names = self._maybe_dedup_names(self.orig_names)
# error: Cannot determine type of 'index_col'
index, columns, col_dict = self._get_empty_meta(
names,
self.index_col, # type: ignore[has-type]
self.index_names,
self.dtype,
)
conv_columns = self._maybe_make_multi_index_columns(columns, self.col_names)
return index, conv_columns, col_dict
# handle new style for names in index
count_empty_content_vals = count_empty_vals(content[0])
indexnamerow = None
if self.has_index_names and count_empty_content_vals == len(columns):
indexnamerow = content[0]
content = content[1:]
alldata = self._rows_to_cols(content)
data, columns = self._exclude_implicit_index(alldata)
conv_data = self._convert_data(data)
columns, conv_data = self._do_date_conversions(columns, conv_data)
index, result_columns = self._make_index(
conv_data, alldata, columns, indexnamerow
)
return index, result_columns, conv_data
def _exclude_implicit_index(
self,
alldata: list[np.ndarray],
) -> tuple[Mapping[Hashable, np.ndarray], Sequence[Hashable]]:
names = self._maybe_dedup_names(self.orig_names)
offset = 0
if self._implicit_index:
# error: Cannot determine type of 'index_col'
offset = len(self.index_col) # type: ignore[has-type]
len_alldata = len(alldata)
self._check_data_length(names, alldata)
return {
name: alldata[i + offset] for i, name in enumerate(names) if i < len_alldata
}, names
# legacy
def get_chunk(
self, size: int | None = None
) -> tuple[
Index | None, Sequence[Hashable] | MultiIndex, Mapping[Hashable, ArrayLike]
]:
if size is None:
# error: "PythonParser" has no attribute "chunksize"
size = self.chunksize # type: ignore[attr-defined]
return self.read(rows=size)
def _convert_data(
self,
data: Mapping[Hashable, np.ndarray],
) -> Mapping[Hashable, ArrayLike]:
# apply converters
clean_conv = self._clean_mapping(self.converters)
clean_dtypes = self._clean_mapping(self.dtype)
# Apply NA values.
clean_na_values = {}
clean_na_fvalues = {}
if isinstance(self.na_values, dict):
for col in self.na_values:
na_value = self.na_values[col]
na_fvalue = self.na_fvalues[col]
if isinstance(col, int) and col not in self.orig_names:
col = self.orig_names[col]
clean_na_values[col] = na_value
clean_na_fvalues[col] = na_fvalue
else:
clean_na_values = self.na_values
clean_na_fvalues = self.na_fvalues
return self._convert_to_ndarrays(
data,
clean_na_values,
clean_na_fvalues,
self.verbose,
clean_conv,
clean_dtypes,
)
def _infer_columns(
self,
) -> tuple[list[list[Scalar | None]], int, set[Scalar | None]]:
names = self.names
num_original_columns = 0
clear_buffer = True
unnamed_cols: set[Scalar | None] = set()
self._header_line = None
if self.header is not None:
header = self.header
if isinstance(header, (list, tuple, np.ndarray)):
have_mi_columns = len(header) > 1
# we have a mi columns, so read an extra line
if have_mi_columns:
header = list(header) + [header[-1] + 1]
else:
have_mi_columns = False
header = [header]
columns: list[list[Scalar | None]] = []
for level, hr in enumerate(header):
try:
line = self._buffered_line()
while self.line_pos <= hr:
line = self._next_line()
except StopIteration as err:
if 0 < self.line_pos <= hr and (
not have_mi_columns or hr != header[-1]
):
# If no rows we want to raise a different message and if
# we have mi columns, the last line is not part of the header
joi = list(map(str, header[:-1] if have_mi_columns else header))
msg = f"[{','.join(joi)}], len of {len(joi)}, "
raise ValueError(
f"Passed header={msg}"
f"but only {self.line_pos} lines in file"
) from err
# We have an empty file, so check
# if columns are provided. That will
# serve as the 'line' for parsing
if have_mi_columns and hr > 0:
if clear_buffer:
self._clear_buffer()
columns.append([None] * len(columns[-1]))
return columns, num_original_columns, unnamed_cols
if not self.names:
raise EmptyDataError("No columns to parse from file") from err
line = self.names[:]
this_columns: list[Scalar | None] = []
this_unnamed_cols = []
for i, c in enumerate(line):
if c == "":
if have_mi_columns:
col_name = f"Unnamed: {i}_level_{level}"
else:
col_name = f"Unnamed: {i}"
this_unnamed_cols.append(i)
this_columns.append(col_name)
else:
this_columns.append(c)
if not have_mi_columns and self.mangle_dupe_cols:
counts: DefaultDict = defaultdict(int)
# Ensure that regular columns are used before unnamed ones
# to keep given names and mangle unnamed columns
col_loop_order = [
i
for i in range(len(this_columns))
if i not in this_unnamed_cols
] + this_unnamed_cols
for i in col_loop_order:
col = this_columns[i]
old_col = col
cur_count = counts[col]
if cur_count > 0:
while cur_count > 0:
counts[old_col] = cur_count + 1
col = f"{old_col}.{cur_count}"
if col in this_columns:
cur_count += 1
else:
cur_count = counts[col]
if (
self.dtype is not None
and is_dict_like(self.dtype)
and self.dtype.get(old_col) is not None
and self.dtype.get(col) is None
):
self.dtype.update({col: self.dtype.get(old_col)})
this_columns[i] = col
counts[col] = cur_count + 1
elif have_mi_columns:
# if we have grabbed an extra line, but its not in our
# format so save in the buffer, and create an blank extra
# line for the rest of the parsing code
if hr == header[-1]:
lc = len(this_columns)
# error: Cannot determine type of 'index_col'
sic = self.index_col # type: ignore[has-type]
ic = len(sic) if sic is not None else 0
unnamed_count = len(this_unnamed_cols)
# if wrong number of blanks or no index, not our format
if (lc != unnamed_count and lc - ic > unnamed_count) or ic == 0:
clear_buffer = False
this_columns = [None] * lc
self.buf = [self.buf[-1]]
columns.append(this_columns)
unnamed_cols.update({this_columns[i] for i in this_unnamed_cols})
if len(columns) == 1:
num_original_columns = len(this_columns)
if clear_buffer:
self._clear_buffer()
first_line: list[Scalar] | None
if names is not None:
# Read first row after header to check if data are longer
try:
first_line = self._next_line()
except StopIteration:
first_line = None
len_first_data_row = 0 if first_line is None else len(first_line)
if len(names) > len(columns[0]) and len(names) > len_first_data_row:
raise ValueError(
"Number of passed names did not match "
"number of header fields in the file"
)
if len(columns) > 1:
raise TypeError("Cannot pass names with multi-index columns")
if self.usecols is not None:
# Set _use_cols. We don't store columns because they are
# overwritten.
self._handle_usecols(columns, names, num_original_columns)
else:
num_original_columns = len(names)
if self._col_indices is not None and len(names) != len(
self._col_indices
):
columns = [[names[i] for i in sorted(self._col_indices)]]
else:
columns = [names]
else:
columns = self._handle_usecols(
columns, columns[0], num_original_columns
)
else:
try:
line = self._buffered_line()
except StopIteration as err:
if not names:
raise EmptyDataError("No columns to parse from file") from err
line = names[:]
# Store line, otherwise it is lost for guessing the index
self._header_line = line
ncols = len(line)
num_original_columns = ncols
if not names:
if self.prefix:
columns = [[f"{self.prefix}{i}" for i in range(ncols)]]
else:
columns = [list(range(ncols))]
columns = self._handle_usecols(
columns, columns[0], num_original_columns
)
else:
if self.usecols is None or len(names) >= num_original_columns:
columns = self._handle_usecols([names], names, num_original_columns)
num_original_columns = len(names)
else:
if not callable(self.usecols) and len(names) != len(self.usecols):
raise ValueError(
"Number of passed names did not match number of "
"header fields in the file"
)
# Ignore output but set used columns.
self._handle_usecols([names], names, ncols)
columns = [names]
num_original_columns = ncols
return columns, num_original_columns, unnamed_cols
def _handle_usecols(
self,
columns: list[list[Scalar | None]],
usecols_key: list[Scalar | None],
num_original_columns: int,
) -> list[list[Scalar | None]]:
"""
Sets self._col_indices
usecols_key is used if there are string usecols.
"""
col_indices: set[int] | list[int]
if self.usecols is not None:
if callable(self.usecols):
col_indices = self._evaluate_usecols(self.usecols, usecols_key)
elif any(isinstance(u, str) for u in self.usecols):
if len(columns) > 1:
raise ValueError(
"If using multiple headers, usecols must be integers."
)
col_indices = []
for col in self.usecols:
if isinstance(col, str):
try:
col_indices.append(usecols_key.index(col))
except ValueError:
self._validate_usecols_names(self.usecols, usecols_key)
else:
col_indices.append(col)
else:
missing_usecols = [
col for col in self.usecols if col >= num_original_columns
]
if missing_usecols:
warnings.warn(
"Defining usecols with out of bounds indices is deprecated "
"and will raise a ParserError in a future version.",
FutureWarning,
stacklevel=find_stack_level(),
)
col_indices = self.usecols
columns = [
[n for i, n in enumerate(column) if i in col_indices]
for column in columns
]
self._col_indices = sorted(col_indices)
return columns
def _buffered_line(self) -> list[Scalar]:
"""
Return a line from buffer, filling buffer if required.
"""
if len(self.buf) > 0:
return self.buf[0]
else:
return self._next_line()
def _check_for_bom(self, first_row: list[Scalar]) -> list[Scalar]:
"""
Checks whether the file begins with the BOM character.
If it does, remove it. In addition, if there is quoting
in the field subsequent to the BOM, remove it as well
because it technically takes place at the beginning of
the name, not the middle of it.
"""
# first_row will be a list, so we need to check
# that that list is not empty before proceeding.
if not first_row:
return first_row
# The first element of this row is the one that could have the
# BOM that we want to remove. Check that the first element is a
# string before proceeding.
if not isinstance(first_row[0], str):
return first_row
# Check that the string is not empty, as that would
# obviously not have a BOM at the start of it.
if not first_row[0]:
return first_row
# Since the string is non-empty, check that it does
# in fact begin with a BOM.
first_elt = first_row[0][0]
if first_elt != _BOM:
return first_row
first_row_bom = first_row[0]
new_row: str
if len(first_row_bom) > 1 and first_row_bom[1] == self.quotechar:
start = 2
quote = first_row_bom[1]
end = first_row_bom[2:].index(quote) + 2
# Extract the data between the quotation marks
new_row = first_row_bom[start:end]
# Extract any remaining data after the second
# quotation mark.
if len(first_row_bom) > end + 1:
new_row += first_row_bom[end + 1 :]
else:
# No quotation so just remove BOM from first element
new_row = first_row_bom[1:]
new_row_list: list[Scalar] = [new_row]
return new_row_list + first_row[1:]
def _is_line_empty(self, line: list[Scalar]) -> bool:
"""
Check if a line is empty or not.
Parameters
----------
line : str, array-like
The line of data to check.
Returns
-------
boolean : Whether or not the line is empty.
"""
return not line or all(not x for x in line)
def _next_line(self) -> list[Scalar]:
if isinstance(self.data, list):
while self.skipfunc(self.pos):
if self.pos >= len(self.data):
break
self.pos += 1
while True:
try:
line = self._check_comments([self.data[self.pos]])[0]
self.pos += 1
# either uncommented or blank to begin with
if not self.skip_blank_lines and (
self._is_line_empty(self.data[self.pos - 1]) or line
):
break
elif self.skip_blank_lines:
ret = self._remove_empty_lines([line])
if ret:
line = ret[0]
break
except IndexError:
raise StopIteration
else:
while self.skipfunc(self.pos):
self.pos += 1
# assert for mypy, data is Iterator[str] or None, would error in next
assert self.data is not None
next(self.data)
while True:
orig_line = self._next_iter_line(row_num=self.pos + 1)
self.pos += 1
if orig_line is not None:
line = self._check_comments([orig_line])[0]
if self.skip_blank_lines:
ret = self._remove_empty_lines([line])
if ret:
line = ret[0]
break
elif self._is_line_empty(orig_line) or line:
break
# This was the first line of the file,
# which could contain the BOM at the
# beginning of it.
if self.pos == 1:
line = self._check_for_bom(line)
self.line_pos += 1
self.buf.append(line)
return line
def _alert_malformed(self, msg: str, row_num: int) -> None:
"""
Alert a user about a malformed row, depending on value of
`self.on_bad_lines` enum.
If `self.on_bad_lines` is ERROR, the alert will be `ParserError`.
If `self.on_bad_lines` is WARN, the alert will be printed out.
Parameters
----------
msg: str
The error message to display.
row_num: int
The row number where the parsing error occurred.
Because this row number is displayed, we 1-index,
even though we 0-index internally.
"""
if self.on_bad_lines == self.BadLineHandleMethod.ERROR:
raise ParserError(msg)
elif self.on_bad_lines == self.BadLineHandleMethod.WARN:
base = f"Skipping line {row_num}: "
sys.stderr.write(base + msg + "\n")
def _next_iter_line(self, row_num: int) -> list[Scalar] | None:
"""
Wrapper around iterating through `self.data` (CSV source).
When a CSV error is raised, we check for specific
error messages that allow us to customize the
error message displayed to the user.
Parameters
----------
row_num: int
The row number of the line being parsed.
"""
try:
# assert for mypy, data is Iterator[str] or None, would error in next
assert self.data is not None
line = next(self.data)
# for mypy
assert isinstance(line, list)
return line
except csv.Error as e:
if (
self.on_bad_lines == self.BadLineHandleMethod.ERROR
or self.on_bad_lines == self.BadLineHandleMethod.WARN
):
msg = str(e)
if "NULL byte" in msg or "line contains NUL" in msg:
msg = (
"NULL byte detected. This byte "
"cannot be processed in Python's "
"native csv library at the moment, "
"so please pass in engine='c' instead"
)
if self.skipfooter > 0:
reason = (
"Error could possibly be due to "
"parsing errors in the skipped footer rows "
"(the skipfooter keyword is only applied "
"after Python's csv library has parsed "
"all rows)."
)
msg += ". " + reason
self._alert_malformed(msg, row_num)
return None
def _check_comments(self, lines: list[list[Scalar]]) -> list[list[Scalar]]:
if self.comment is None:
return lines
ret = []
for line in lines:
rl = []
for x in line:
if (
not isinstance(x, str)
or self.comment not in x
or x in self.na_values
):
rl.append(x)
else:
x = x[: x.find(self.comment)]
if len(x) > 0:
rl.append(x)
break
ret.append(rl)
return ret
def _remove_empty_lines(self, lines: list[list[Scalar]]) -> list[list[Scalar]]:
"""
Iterate through the lines and remove any that are
either empty or contain only one whitespace value
Parameters
----------
lines : list of list of Scalars
The array of lines that we are to filter.
Returns
-------
filtered_lines : list of list of Scalars
The same array of lines with the "empty" ones removed.
"""
ret = []
for line in lines:
# Remove empty lines and lines with only one whitespace value
if (
len(line) > 1
or len(line) == 1
and (not isinstance(line[0], str) or line[0].strip())
):
ret.append(line)
return ret
def _check_thousands(self, lines: list[list[Scalar]]) -> list[list[Scalar]]:
if self.thousands is None:
return lines
return self._search_replace_num_columns(
lines=lines, search=self.thousands, replace=""
)
def _search_replace_num_columns(
self, lines: list[list[Scalar]], search: str, replace: str
) -> list[list[Scalar]]:
ret = []
for line in lines:
rl = []
for i, x in enumerate(line):
if (
not isinstance(x, str)
or search not in x
or (self._no_thousands_columns and i in self._no_thousands_columns)
or not self.num.search(x.strip())
):
rl.append(x)
else:
rl.append(x.replace(search, replace))
ret.append(rl)
return ret
def _check_decimal(self, lines: list[list[Scalar]]) -> list[list[Scalar]]:
if self.decimal == parser_defaults["decimal"]:
return lines
return self._search_replace_num_columns(
lines=lines, search=self.decimal, replace="."
)
def _clear_buffer(self) -> None:
self.buf = []
_implicit_index = False
def _get_index_name(
self, columns: list[Hashable]
) -> tuple[Sequence[Hashable] | None, list[Hashable], list[Hashable]]:
"""
Try several cases to get lines:
0) There are headers on row 0 and row 1 and their
total summed lengths equals the length of the next line.
Treat row 0 as columns and row 1 as indices
1) Look for implicit index: there are more columns
on row 1 than row 0. If this is true, assume that row
1 lists index columns and row 0 lists normal columns.
2) Get index from the columns if it was listed.
"""
orig_names = list(columns)
columns = list(columns)
line: list[Scalar] | None
if self._header_line is not None:
line = self._header_line
else:
try:
line = self._next_line()
except StopIteration:
line = None
next_line: list[Scalar] | None
try:
next_line = self._next_line()
except StopIteration:
next_line = None
# implicitly index_col=0 b/c 1 fewer column names
implicit_first_cols = 0
if line is not None:
# leave it 0, #2442
# Case 1
# error: Cannot determine type of 'index_col'
index_col = self.index_col # type: ignore[has-type]
if index_col is not False:
implicit_first_cols = len(line) - self.num_original_columns
# Case 0
if (
next_line is not None
and self.header is not None
and index_col is not False
):
if len(next_line) == len(line) + self.num_original_columns:
# column and index names on diff rows
self.index_col = list(range(len(line)))
self.buf = self.buf[1:]
for c in reversed(line):
columns.insert(0, c)
# Update list of original names to include all indices.
orig_names = list(columns)
self.num_original_columns = len(columns)
return line, orig_names, columns
if implicit_first_cols > 0:
# Case 1
self._implicit_index = True
if self.index_col is None:
self.index_col = list(range(implicit_first_cols))
index_name = None
else:
# Case 2
(index_name, _, self.index_col) = self._clean_index_names(
columns, self.index_col
)
return index_name, orig_names, columns
def _rows_to_cols(self, content: list[list[Scalar]]) -> list[np.ndarray]:
col_len = self.num_original_columns
if self._implicit_index:
col_len += len(self.index_col)
max_len = max(len(row) for row in content)
# Check that there are no rows with too many
# elements in their row (rows with too few
# elements are padded with NaN).
# error: Non-overlapping identity check (left operand type: "List[int]",
# right operand type: "Literal[False]")
if (
max_len > col_len
and self.index_col is not False # type: ignore[comparison-overlap]
and self.usecols is None
):
footers = self.skipfooter if self.skipfooter else 0
bad_lines = []
iter_content = enumerate(content)
content_len = len(content)
content = []
for (i, l) in iter_content:
actual_len = len(l)
if actual_len > col_len:
if callable(self.on_bad_lines):
new_l = self.on_bad_lines(l)
if new_l is not None:
content.append(new_l)
elif (
self.on_bad_lines == self.BadLineHandleMethod.ERROR
or self.on_bad_lines == self.BadLineHandleMethod.WARN
):
row_num = self.pos - (content_len - i + footers)
bad_lines.append((row_num, actual_len))
if self.on_bad_lines == self.BadLineHandleMethod.ERROR:
break
else:
content.append(l)
for row_num, actual_len in bad_lines:
msg = (
f"Expected {col_len} fields in line {row_num + 1}, saw "
f"{actual_len}"
)
if (
self.delimiter
and len(self.delimiter) > 1
and self.quoting != csv.QUOTE_NONE
):
# see gh-13374
reason = (
"Error could possibly be due to quotes being "
"ignored when a multi-char delimiter is used."
)
msg += ". " + reason
self._alert_malformed(msg, row_num + 1)
# see gh-13320
zipped_content = list(lib.to_object_array(content, min_width=col_len).T)
if self.usecols:
assert self._col_indices is not None
col_indices = self._col_indices
if self._implicit_index:
zipped_content = [
a
for i, a in enumerate(zipped_content)
if (
i < len(self.index_col)
or i - len(self.index_col) in col_indices
)
]
else:
zipped_content = [
a for i, a in enumerate(zipped_content) if i in col_indices
]
return zipped_content
def _get_lines(self, rows: int | None = None) -> list[list[Scalar]]:
lines = self.buf
new_rows = None
# already fetched some number
if rows is not None:
# we already have the lines in the buffer
if len(self.buf) >= rows:
new_rows, self.buf = self.buf[:rows], self.buf[rows:]
# need some lines
else:
rows -= len(self.buf)
if new_rows is None:
if isinstance(self.data, list):
if self.pos > len(self.data):
raise StopIteration
if rows is None:
new_rows = self.data[self.pos :]
new_pos = len(self.data)
else:
new_rows = self.data[self.pos : self.pos + rows]
new_pos = self.pos + rows
new_rows = self._remove_skipped_rows(new_rows)
lines.extend(new_rows)
self.pos = new_pos
else:
new_rows = []
try:
if rows is not None:
rows_to_skip = 0
if self.skiprows is not None and self.pos is not None:
# Only read additional rows if pos is in skiprows
rows_to_skip = len(
set(self.skiprows) - set(range(self.pos))
)
for _ in range(rows + rows_to_skip):
# assert for mypy, data is Iterator[str] or None, would
# error in next
assert self.data is not None
new_rows.append(next(self.data))
len_new_rows = len(new_rows)
new_rows = self._remove_skipped_rows(new_rows)
lines.extend(new_rows)
else:
rows = 0
while True:
new_row = self._next_iter_line(row_num=self.pos + rows + 1)
rows += 1
if new_row is not None:
new_rows.append(new_row)
len_new_rows = len(new_rows)
except StopIteration:
len_new_rows = len(new_rows)
new_rows = self._remove_skipped_rows(new_rows)
lines.extend(new_rows)
if len(lines) == 0:
raise
self.pos += len_new_rows
self.buf = []
else:
lines = new_rows
if self.skipfooter:
lines = lines[: -self.skipfooter]
lines = self._check_comments(lines)
if self.skip_blank_lines:
lines = self._remove_empty_lines(lines)
lines = self._check_thousands(lines)
return self._check_decimal(lines)
def _remove_skipped_rows(self, new_rows: list[list[Scalar]]) -> list[list[Scalar]]:
if self.skiprows:
return [
row for i, row in enumerate(new_rows) if not self.skipfunc(i + self.pos)
]
return new_rows
class FixedWidthReader(abc.Iterator):
"""
A reader of fixed-width lines.
"""
def __init__(
self,
f: IO[str] | ReadCsvBuffer[str],
colspecs: list[tuple[int, int]] | Literal["infer"],
delimiter: str | None,
comment: str | None,
skiprows: set[int] | None = None,
infer_nrows: int = 100,
) -> None:
self.f = f
self.buffer: Iterator | None = None
self.delimiter = "\r\n" + delimiter if delimiter else "\n\r\t "
self.comment = comment
if colspecs == "infer":
self.colspecs = self.detect_colspecs(
infer_nrows=infer_nrows, skiprows=skiprows
)
else:
self.colspecs = colspecs
if not isinstance(self.colspecs, (tuple, list)):
raise TypeError(
"column specifications must be a list or tuple, "
f"input was a {type(colspecs).__name__}"
)
for colspec in self.colspecs:
if not (
isinstance(colspec, (tuple, list))
and len(colspec) == 2
and isinstance(colspec[0], (int, np.integer, type(None)))
and isinstance(colspec[1], (int, np.integer, type(None)))
):
raise TypeError(
"Each column specification must be "
"2 element tuple or list of integers"
)
def get_rows(self, infer_nrows: int, skiprows: set[int] | None = None) -> list[str]:
"""
Read rows from self.f, skipping as specified.
We distinguish buffer_rows (the first <= infer_nrows
lines) from the rows returned to detect_colspecs
because it's simpler to leave the other locations
with skiprows logic alone than to modify them to
deal with the fact we skipped some rows here as
well.
Parameters
----------
infer_nrows : int
Number of rows to read from self.f, not counting
rows that are skipped.
skiprows: set, optional
Indices of rows to skip.
Returns
-------
detect_rows : list of str
A list containing the rows to read.
"""
if skiprows is None:
skiprows = set()
buffer_rows = []
detect_rows = []
for i, row in enumerate(self.f):
if i not in skiprows:
detect_rows.append(row)
buffer_rows.append(row)
if len(detect_rows) >= infer_nrows:
break
self.buffer = iter(buffer_rows)
return detect_rows
def detect_colspecs(
self, infer_nrows: int = 100, skiprows: set[int] | None = None
) -> list[tuple[int, int]]:
# Regex escape the delimiters
delimiters = "".join([rf"\{x}" for x in self.delimiter])
pattern = re.compile(f"([^{delimiters}]+)")
rows = self.get_rows(infer_nrows, skiprows)
if not rows:
raise EmptyDataError("No rows from which to infer column width")
max_len = max(map(len, rows))
mask = np.zeros(max_len + 1, dtype=int)
if self.comment is not None:
rows = [row.partition(self.comment)[0] for row in rows]
for row in rows:
for m in pattern.finditer(row):
mask[m.start() : m.end()] = 1
shifted = np.roll(mask, 1)
shifted[0] = 0
edges = np.where((mask ^ shifted) == 1)[0]
edge_pairs = list(zip(edges[::2], edges[1::2]))
return edge_pairs
def __next__(self) -> list[str]:
# Argument 1 to "next" has incompatible type "Union[IO[str],
# ReadCsvBuffer[str]]"; expected "SupportsNext[str]"
if self.buffer is not None:
try:
line = next(self.buffer)
except StopIteration:
self.buffer = None
line = next(self.f) # type: ignore[arg-type]
else:
line = next(self.f) # type: ignore[arg-type]
# Note: 'colspecs' is a sequence of half-open intervals.
return [line[fromm:to].strip(self.delimiter) for (fromm, to) in self.colspecs]
class FixedWidthFieldParser(PythonParser):
"""
Specialization that Converts fixed-width fields into DataFrames.
See PythonParser for details.
"""
def __init__(self, f: ReadCsvBuffer[str], **kwds) -> None:
# Support iterators, convert to a list.
self.colspecs = kwds.pop("colspecs")
self.infer_nrows = kwds.pop("infer_nrows")
PythonParser.__init__(self, f, **kwds)
def _make_reader(self, f: IO[str] | ReadCsvBuffer[str]) -> None:
self.data = FixedWidthReader(
f,
self.colspecs,
self.delimiter,
self.comment,
self.skiprows,
self.infer_nrows,
)
def _remove_empty_lines(self, lines: list[list[Scalar]]) -> list[list[Scalar]]:
"""
Returns the list of lines without the empty ones. With fixed-width
fields, empty lines become arrays of empty strings.
See PythonParser._remove_empty_lines.
"""
return [
line
for line in lines
if any(not isinstance(e, str) or e.strip() for e in line)
]
def count_empty_vals(vals) -> int:
return sum(1 for v in vals if v == "" or v is None)
def _validate_skipfooter_arg(skipfooter: int) -> int:
"""
Validate the 'skipfooter' parameter.
Checks whether 'skipfooter' is a non-negative integer.
Raises a ValueError if that is not the case.
Parameters
----------
skipfooter : non-negative integer
The number of rows to skip at the end of the file.
Returns
-------
validated_skipfooter : non-negative integer
The original input if the validation succeeds.
Raises
------
ValueError : 'skipfooter' was not a non-negative integer.
"""
if not is_integer(skipfooter):
raise ValueError("skipfooter must be an integer")
if skipfooter < 0:
raise ValueError("skipfooter cannot be negative")
return skipfooter