Given a date range how can we break it up into N contiguous sub-intervals?

Question

I am accessing some data through an API where I need to provide the date range for my request, ex. start=\'20100101\', end=\'20150415\'. I thought I would speed this up by

Answer 1

Using Datetimeindex and Periods from Pandas, together with dictionary comprehension:

import pandas as pd

begin = '20100101'
end = '20101231'

start = dt.datetime.strptime(begin, '%Y%m%d')
finish = dt.datetime.strptime(end, '%Y%m%d')

dates = pd.DatetimeIndex(start=start, end=finish, freq='D').tolist()
quarters = [d.to_period('Q') for d in dates]
df = pd.DataFrame([quarters, dates], index=['Quarter', 'Date']).T

quarterly_dates = {str(q): [ts.strftime('%Y%m%d') 
                            for ts in df[df.Quarter == q].Date.values.tolist()]
                           for q in quarters}

>>> quarterly_dates
{'2010Q1': ['20100101',
  '20100102',
  '20100103',
  '20100104',
  '20100105',
...
  '20101227',
  '20101228',
  '20101229',
  '20101230',
  '20101231']}

>>> quarterly_dates.keys()
['2010Q1', '2010Q2', '2010Q3', '2010Q4']