utils.py

>>> import datetime
>>> import numpy
>>> epsilon = 0.00001

def update_dates(dates, timestep, unitofstep, deduceaday=False):

Adds the specified amount of time to the given dates and returns the result

>>> from simo.utils.utils import update_dates
>>> dates = (datetime.date(2000,1,1),
...          datetime.date(2001,1,1),
...          datetime.date(2002,1,1),)
>>> update_dates(dates, 5, 'year') 
array([...2005...1...1..., ...2006...1...1..., ...2007...1...1...],
      dtype=object)
>>> update_dates(dates, 5, 'year', True)
array([...2004...12...31..., ...2005...12...31..., ...2006...12...31...],
       dtype=object)

def update_date(curdate, timestep, unitofstep, deduceaday=False):

Adds the specified amount of time to the current date and returns the result

>>> from simo.utils.utils import update_date
>>> update_date(datetime.date(2000,1,1), 5, 'year')
datetime.date(2005, 1, 1)
>>> update_date(datetime.date(2000,1,1), 5, 'year', True)
datetime.date(2004, 12, 31)

def calculate_date_diff(start, end, unit):

Calculate the difference two dates in given units

>>> from simo.utils.utils import calculate_date_diff
>>> calculate_date_diff(datetime.date(2000,1,1),
...                     datetime.date(2004,12,31), 'year')
5
>>> calculate_date_diff(datetime.date(2000,1,1),
...                     datetime.date(2004,4,1), 'year')
4
>>> calculate_date_diff(datetime.date(2000,1,1),
...                     datetime.date(1993,12,31), 'year')
-7

def str2date(text, sep=’-‘, order=’year first’):

Parse a date string from xml (type ‘xs:date’) or generic string to a datetime object

>>> from simo.utils.utils import str2date
>>> str2date('2010-01-01')
datetime.date(2010, 1, 1)
>>> str2date('2010.01.01', sep='.')
datetime.date(2010, 1, 1)
>>> str2date('1/1/2010', sep='/', order='day first')
datetime.date(2010, 1, 1)

def str2bool(text):

Parse a boolean string from xml (type ‘xs:boolean’) to boolean value

>>> from simo.utils.utils import str2bool
>>> str2bool('TRUE')
True
>>> str2bool('True')
True
>>> str2bool('true')
True
>>> str2bool('FALSE')
False
>>> str2bool('False')
False
>>> str2bool('false')
False
>>> str2bool('xyz')
False

def secs2str(seconds):

Convert seconds into hh:mm:ss.ss string

>>> from simo.utils.utils import secs2str
>>> secs2str(1.5)
'00:00:1.500'
>>> secs2str(121.9)
'00:02:1.900'
>>> secs2str(5121.9)
'01:25:21.900'

def calculate_NPV(value, discountrate, presentdate, eventdate):

Calculate the discounted NPV (Net Present Value) for a single value or vector:

>>> from simo.utils.utils import calculate_NPV
>>> npv = calculate_NPV(100.0, 5.0, datetime.date(2000,1,1),
...                     datetime.date(2010,1,1))
>>> abs(npv - 61.366711) < epsilon
True
>>> npv = calculate_NPV(100.0, 5.0, datetime.date(2000,1,1),
...                     datetime.date(2010,7,31))
>>> abs(npv - 59.660061) < epsilon
True
>>> npv = calculate_NPV(100.0, 5.0, datetime.date(2000,1,1),
...                     datetime.date(2010,12,28))
>>> abs(npv - 58.475745) < epsilon
True
>>> npv = calculate_NPV(100.0, 5.0, datetime.date(2000,1,1),
...                     datetime.date(2010,12,31))
>>> abs(npv - 58.452299) < epsilon
True
>>> values = numpy.array([100, 100, 100], dtype=float)
>>> npv = calculate_NPV(values, 5.0, datetime.date(2000,1,1),
...                     datetime.date(2010,1,1))
>>> abs(npv - 61.366711) < epsilon
array([ True,  True,  True], dtype=bool)