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""" 17Merge mutliple CSV files, possibly with different columns, writing to stdout. 18""" 19 20import csv 21import sys 22 23csv_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: 29headers = set() 30for reader in csv_readers: 31 headers = headers.union(reader.fieldnames) 32 33# Concatenate all files to output: 34out = csv.DictWriter(sys.stdout, delimiter=',', quotechar='|', fieldnames = sorted(headers)) 35out.writeheader() 36for reader in csv_readers: 37 for row in reader: 38 out.writerow(row) 39 40 41