84c1cdf31f
Previously, if the --header property was not specified then merge_csv
would use a header constructed by sorting all the fields in the input
files. That required that any use of merge_csv which did not already
have headers in the required order would have to explicitly specify the
headers. That made it harder to use merge_csv as a generic tool as each
invocation needed to be aware of what headers were exported in the
output.
This change causes merge_csv to simply use the headers in the order in
which they are encountered in the input files. That removes the need to
specify the --header option when generating the index files.
Bug: 179354495
Test: m out/soong/hiddenapi/hiddenapi-index.csv out/soong/hiddenapi/hiddenapi-unsupported.csv
- make sure that they are not changed by this change.
Change-Id: I420b7d07aea85af6372cd7580a8be5e2cc82a513
93 lines
3.6 KiB
Python
Executable file
93 lines
3.6 KiB
Python
Executable file
#!/usr/bin/env python
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#
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# Copyright (C) 2018 The Android Open Source Project
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Merge multiple CSV files, possibly with different columns.
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"""
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import argparse
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import csv
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import io
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import heapq
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import itertools
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import operator
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from zipfile import ZipFile
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args_parser = argparse.ArgumentParser(description='Merge given CSV files into a single one.')
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args_parser.add_argument('--header', help='Comma separated field names; '
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'if missing determines the header from input files.')
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args_parser.add_argument('--zip_input', help='Treat files as ZIP archives containing CSV files to merge.',
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action="store_true")
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args_parser.add_argument('--key_field', help='The name of the field by which the rows should be sorted. '
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'Must be in the field names. '
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'Will be the first field in the output. '
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'All input files must be sorted by that field.')
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args_parser.add_argument('--output', help='Output file for merged CSV.',
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default='-', type=argparse.FileType('w'))
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args_parser.add_argument('files', nargs=argparse.REMAINDER)
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args = args_parser.parse_args()
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def dict_reader(input):
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return csv.DictReader(input, delimiter=',', quotechar='|')
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csv_readers = []
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if not(args.zip_input):
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for file in args.files:
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csv_readers.append(dict_reader(open(file, 'r')))
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else:
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for file in args.files:
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with ZipFile(file) as zip:
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for entry in zip.namelist():
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if entry.endswith('.uau'):
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csv_readers.append(dict_reader(io.TextIOWrapper(zip.open(entry, 'r'))))
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if args.header:
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fieldnames = args.header.split(',')
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else:
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headers = {}
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# Build union of all columns from source files:
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for reader in csv_readers:
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for fieldname in reader.fieldnames:
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headers[fieldname] = ""
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fieldnames = list(headers.keys())
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# By default chain the csv readers together so that the resulting output is
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# the concatenation of the rows from each of them:
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all_rows = itertools.chain.from_iterable(csv_readers)
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if len(csv_readers) > 0:
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keyField = args.key_field
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if keyField:
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assert keyField in fieldnames, (
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"--key_field {} not found, must be one of {}\n").format(
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keyField, ",".join(fieldnames))
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# Make the key field the first field in the output
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keyFieldIndex = fieldnames.index(args.key_field)
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fieldnames.insert(0, fieldnames.pop(keyFieldIndex))
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# Create an iterable that performs a lazy merge sort on the csv readers
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# sorting the rows by the key field.
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all_rows = heapq.merge(*csv_readers, key=operator.itemgetter(keyField))
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# Write all rows from the input files to the output:
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writer = csv.DictWriter(args.output, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL,
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dialect='unix', fieldnames=fieldnames)
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writer.writeheader()
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# Read all the rows from the input and write them to the output in the correct
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# order:
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for row in all_rows:
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writer.writerow(row)
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