process time period string like 'w', 'd', 'h', 'm' , 's'

convert_to_seconds.py

from datetime import timedelta
import re

UNITS = {"s":"seconds", "m":"minutes", "h":"hours", "d":"days", "w":"weeks"}
def convert_to_seconds(s):
    params = {}
    for amount, u in re.findall(r'(?:(\d+)([smhdw])\s*)', s):
        u = UNITS[u]
        amount = int(amount)
        if u in params:
            raise Exception('duplicate unit %s' % u)
        params[u] = amount
    td = timedelta(**params)
    return int(td.total_seconds())



print convert_to_seconds('1m30s')  # 90
print convert_to_seconds('3m')  # 180
print convert_to_seconds('1h')  # 10800
print convert_to_seconds('1h18m36s')  # 4716