Pivot a CSV table.

pivot_csv.py

#!/usr/bin/env python

import sys
import csv
import tornado.options
from collections import defaultdict

def run():
    data = defaultdict(dict)
    columns = set()
    o = tornado.options.options
    for line in csv.reader(sys.stdin):
        columns.add(line[o.pivot_column])
        data[line[o.row_column]][line[o.pivot_column]] = line[o.value_column]
    
    columns = sorted(columns)
    w = csv.writer(sys.stdout)
    w.writerow(['key'] + columns)
    for key, row_data in data.items():
        row = [key]
        for column in columns:
            row.append(row_data.get(column, ''))
        w.writerow(row)
        

if __name__ == "__main__":
    tornado.options.define("pivot_column", default=1, type=int, help="column to pivot on (starting at 0)")
    tornado.options.define("row_column", default=0, type=int, help="key for rows (starting at 0)")
    tornado.options.define("value_column", default=2, type=int, help="value for rows (starting at 0)")
    tornado.options.parse_command_line()
    run()