csv writer to csv interface with reader class
But this is more for reference and should not be considered final Missing things are like - all values to private - reader interface to parts - value check for delimiter, quotechar, etc
This commit is contained in:
Clemens Schwaighofer
148
src/corelibs/csv_handling/csv_interface.py
Normal file
148
src/corelibs/csv_handling/csv_interface.py
Normal file
@@ -0,0 +1,148 @@
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"""
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Write to CSV file
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- each class set is one file write with one header set
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"""
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from typing import Any, Sequence
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from pathlib import Path
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from collections import Counter
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import csv
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DELIMITER = ","
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QUOTECHAR = '"'
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# type: _QuotingType
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QUOTING = csv.QUOTE_MINIMAL
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class CsvWriter:
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"""
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write to a CSV file
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"""
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def __init__(
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self,
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file_name: Path,
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header_mapping: dict[str, str],
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header_order: list[str] | None = None,
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delimiter: str = DELIMITER,
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quotechar: str = QUOTECHAR,
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quoting: Any = QUOTING,
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):
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self.__file_name = file_name
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# Key: index for write for the line dict, Values: header entries
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self.header_mapping = header_mapping
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self.header: Sequence[str] = list(header_mapping.values())
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self.__delimiter = delimiter
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self.__quotechar = quotechar
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self.__quoting = quoting
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self.csv_file_writer = self.__open_csv(header_order)
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def __open_csv(self, header_order: list[str] | None) -> csv.DictWriter[str]:
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"""
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open csv file for writing, write headers
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Note that if there is no header_order set we use the order in header dictionary
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Arguments:
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line {list[str] | None} -- optional dedicated header order
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Returns:
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csv.DictWriter[str] | None: _description_
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"""
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# if header order is set, make sure all header value fields exist
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header_values = self.header
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if header_order is not None:
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if Counter(header_values) != Counter(header_order):
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raise ValueError(
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"header order does not match header values: "
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f"{', '.join(header_values)} != {', '.join(header_order)}"
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)
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header_values = header_order
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# no duplicates
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if len(header_values) != len(set(header_values)):
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raise ValueError(f"Header must have unique values only: {', '.join(header_values)}")
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try:
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fp = open(
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self.__file_name,
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"w", encoding="utf-8"
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)
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csv_file_writer = csv.DictWriter(
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fp,
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fieldnames=header_values,
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delimiter=self.__delimiter,
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quotechar=self.__quotechar,
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quoting=self.__quoting,
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)
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csv_file_writer.writeheader()
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return csv_file_writer
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except OSError as err:
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raise ValueError(f"Could not open CSV file for writing: {err}") from err
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def write_csv(self, line: dict[str, str]) -> None:
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"""
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write member csv line
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Arguments:
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line {dict[str, str]} -- _description_
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Returns:
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bool -- _description_
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"""
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csv_row: dict[str, Any] = {}
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# only write entries that are in the header list
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for key, value in self.header_mapping.items():
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csv_row[value] = line[key]
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self.csv_file_writer.writerow(csv_row)
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class CsvReader:
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"""
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read from a CSV file
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"""
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def __init__(
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self,
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file_name: Path,
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header_check: Sequence[str] | None = None,
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delimiter: str = DELIMITER,
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quotechar: str = QUOTECHAR,
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quoting: Any = QUOTING,
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):
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self.__file_name = file_name
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self.__header_check = header_check
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self.__delimiter = delimiter
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self.__quotechar = quotechar
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self.__quoting = quoting
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self.header: Sequence[str] | None = None
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self.csv_file_reader = self.__open_csv()
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def __open_csv(self) -> csv.DictReader[str]:
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"""
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open csv file for reading
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Returns:
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csv.DictReader | None: _description_
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"""
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try:
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fp = open(
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self.__file_name,
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"r", encoding="utf-8"
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)
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csv_file_reader = csv.DictReader(
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fp,
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delimiter=self.__delimiter,
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quotechar=self.__quotechar,
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quoting=self.__quoting,
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)
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self.header = csv_file_reader.fieldnames
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if self.__header_check is not None:
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header_diff = set(self.__header_check).difference(set(self.header or []))
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if header_diff:
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raise ValueError(
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f"CSV header does not match expected header: {', '.join(header_diff)} missing"
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)
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return csv_file_reader
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except OSError as err:
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raise ValueError(f"Could not open CSV file for reading: {err}") from err
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# __END__
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@@ -1,93 +0,0 @@
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"""
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Write to CSV file
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- each class set is one file write with one header set
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"""
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from typing import Any
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from pathlib import Path
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from collections import Counter
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import csv
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class CsvWriter:
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"""
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write to a CSV file
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"""
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def __init__(
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self,
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path: Path,
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file_name: str,
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header: dict[str, str],
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header_order: list[str] | None = None
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):
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self.path = path
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self.file_name = file_name
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# Key: index for write for the line dict, Values: header entries
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self.header = header
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self.csv_file_writer = self.__open_csv(header_order)
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def __open_csv(self, header_order: list[str] | None) -> 'csv.DictWriter[str] | None':
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"""
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open csv file for writing, write headers
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Note that if there is no header_order set we use the order in header dictionary
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Arguments:
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line {list[str] | None} -- optional dedicated header order
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Returns:
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csv.DictWriter[str] | None: _description_
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"""
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# if header order is set, make sure all header value fields exist
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header_values = self.header.values()
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if header_order is not None:
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if Counter(header_values) != Counter(header_order):
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print(
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"header order does not match header values: "
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f"{', '.join(header_values)} != {', '.join(header_order)}"
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)
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return None
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header_values = header_order
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# no duplicates
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if len(header_values) != len(set(header_values)):
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print(f"Header must have unique values only: {', '.join(header_values)}")
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return None
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try:
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fp = open(
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self.path.joinpath(self.file_name),
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"w", encoding="utf-8"
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)
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csv_file_writer = csv.DictWriter(
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fp,
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fieldnames=header_values,
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delimiter=",",
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quotechar='"',
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quoting=csv.QUOTE_MINIMAL,
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)
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csv_file_writer.writeheader()
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return csv_file_writer
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except OSError as err:
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print("OS error:", err)
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return None
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def write_csv(self, line: dict[str, str]) -> bool:
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"""
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write member csv line
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Arguments:
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line {dict[str, str]} -- _description_
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Returns:
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bool -- _description_
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"""
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if self.csv_file_writer is None:
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return False
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csv_row: dict[str, Any] = {}
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# only write entries that are in the header list
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for key, value in self.header.items():
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csv_row[value] = line[key]
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self.csv_file_writer.writerow(csv_row)
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return True
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# __END__
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