1 #!/usr/bin/env python 2 # 3 # Copyright (C) 2018 The Android Open Source Project 4 # 5 # Licensed under the Apache License, Version 2.0 (the "License"); 6 # you may not use this file except in compliance with the License. 7 # You may obtain a copy of the License at 8 # 9 # http://www.apache.org/licenses/LICENSE-2.0 10 # 11 # Unless required by applicable law or agreed to in writing, software 12 # distributed under the License is distributed on an "AS IS" BASIS, 13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 # See the License for the specific language governing permissions and 15 # limitations under the License. 16 """ 17 Merge mutliple CSV files, possibly with different columns, writing to stdout. 18 """ 19 20 import csv 21 import sys 22 23 csv_readers = [ 24 csv.DictReader(open(csv_file, 'rb'), delimiter=',', quotechar='|') 25 for csv_file in sys.argv[1:] 26 ] 27 28 # Build union of all columns from source files: 29 headers = set() 30 for reader in csv_readers: 31 headers = headers.union(reader.fieldnames) 32 33 # Concatenate all files to output: 34 out = csv.DictWriter(sys.stdout, delimiter=',', quotechar='|', fieldnames = sorted(headers)) 35 out.writeheader() 36 for reader in csv_readers: 37 for row in reader: 38 out.writerow(row) 39 40 41
