48 lines
1.4 KiB
Python
48 lines
1.4 KiB
Python
# fileparse.py
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import csv
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def parse_csv(lines, select=None, types=None, has_headers=True, delimiter=',', silence_errors=False):
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'''
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Parse a CSV file into a list of records with type conversion.
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'''
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if select and not has_headers:
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raise RuntimeError('select requires column headers')
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rows = csv.reader(lines, delimiter=delimiter)
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# Read the file headers (if any)
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headers = next(rows) if has_headers else []
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# If specific columns have been selected, make indices for filtering and set output columns
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if select:
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indices = [ headers.index(colname) for colname in select ]
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headers = select
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records = []
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for rowno, row in enumerate(rows, 1):
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if not row: # Skip rows with no data
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continue
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# If specific column indices are selected, pick them out
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if select:
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row = [ row[index] for index in indices]
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# Apply type conversion to the row
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if types:
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try:
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row = [func(val) for func, val in zip(types, row)]
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except ValueError as e:
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if not silence_errors:
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print(f"Row {rowno}: Couldn't convert {row}")
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print(f"Row {rowno}: Reason {e}")
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continue
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# Make a dictionary or a tuple
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if headers:
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record = dict(zip(headers, row))
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else:
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record = tuple(row)
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records.append(record)
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return records
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