interval.py

# usage: python interval.py /path/to/your/file.csv

import csv
import sys
import re


def days_from_interval(interval):
    if interval == 'never':
        return None

    days_ago = 0

    years = (r'\d{1,}(?= years?)', 365)
    months = (r'\d{1,}(?= months?)', 30)
    weeks = (r'\d{1,}(?= weeks?)', 7)
    days = (r'\d{1,}(?= days?)', 1)

    for pattern, multiplier in (years, months, weeks, days):
        match = re.search(pattern, interval)

        if match:
            product = int(match.group(0)) * multiplier
        else:
            product = 0

        days_ago += product

    return days_ago


if __name__ == '__main__':
    _, infile = sys.argv

    with open(infile, 'r') as f:
        reader = csv.reader(f)
        writer = csv.writer(sys.stdout)

        writer.writerow(next(reader))

        for row in reader:
            row[2] = days_from_interval(row[2])
            row[3] = days_from_interval(row[3])
            writer.writerow(row)