pick_csv.py

import csv
import sys

try:
    column_indexes = list(map(int, sys.argv[1:]))
except ValueError:
    sys.stderr.write("Usage: python pick_csv.py 0 1 2...\n")
    sys.exit(1)

if len(column_indexes) == 0:
    sys.stderr.write("No output columns? Skipping early.\n")
    sys.exit(0)

input = csv.reader(sys.stdin)
output = csv.writer(sys.stdout)

for in_row in input:
    out_row = []
    for column_index in column_indexes:
        out_row.append(in_row[column_index])
    output.writerow(out_row)