run foo.py with different date input in parallel

parallel.py

# run foo.py with different date input in parallel
# input: sys.argv[1]: starting date ; sys.argv[2]): num of days 

import sys
import os
from multiprocessing import Process
import pandas as pd 

children = []


def get_days_ranges(start, num):
    ''' generate a list containing num of days starting from the starting date'''
    date_range = pd.date_range(start, periods=num, freq='1D')
    date_range = map(lambda dt: dt.strftime("%Y-%m-%d"), date_range)
    days_ranges = [date_range[i] for i in range(0, len(date_range)-1)]
    return days_ranges

days = get_days_ranges(str(sys.argv[1]), int(sys.argv[2] ))

def f(x):
    os.system("python foo.py --date %s" % x)

for x in days:
    p = Process(target=f, args=(x,))
    p.start()
    children.append(p)

for x in children:
    x.join()

  
# merge all temp results
filenames = glob.glob("*.csv")
merge = pd.read_csv(filenames.pop())

for filename in filenames:
	merge = merge.append(pd.read_csv(filename))

del temp['Unnamed: 0']
	
merge.to_csv('bar.csv', index = False)