Calculate date 5 days from today, adding an extra day for each day in the next 5 days that is a weekend day

问题

I am testing using Robot Framework and need to create my own Python keyword.

Taking the current date as day 0 (tomorrow as day 1), I am trying to calculate what the date will be 5 days from today. If any of the days in the next 5 days is a Saturday I need to add an extra day to my calculation. Same if any of the days is a Sunday.

As a Python beginner, I'm a little out of my depth so any help would be much appreciated

回答1:

Basically you need to add 5 business days... This should do it:

import datetime
def addBusinessDays(from_date, add_days):
    business_days_to_add = add_days
    current_date = from_date
    while business_days_to_add > 0:
        current_date += datetime.timedelta(days=1)
        weekday = current_date.weekday()
        if weekday >= 5: # sunday = 6
            continue
        business_days_to_add -= 1
    return current_date

#demo:
print '5 business days from today:'
print addBusinessDays(datetime.date.today(), 5)

Update:

Here is the explanation:

We get the start date(Date that we need to add business days to it)
We use a loop to add days 1 at a time to the date(we use datetime.timedelta(days=1) to add 1 day to date)
After adding each day we check to see if updated date is weekday. If it's weekday we count it otherwise we don't count it and continue

回答2:

You can do it mathematically:

from datetime import timedelta

def business_days(date, days):
    if days == 0:
        return date
    day = date.weekday()
    if day in (5, 6):
        date += timedelta(days=7 - day)
        days -= 1
    date += timedelta(days=days / 5 * 7)
    return date + timedelta(days=days % 5)

It will work to get a date n business days from or since whatever date you pass in:

In [6]: dte = datetime.datetime.today()

In [7]: business_days(dte, 5)
Out[7]: datetime.datetime(2016, 1, 6, 11, 28, 38, 264331)

In [8]: business_days(dte, -5)
Out[8]: datetime.datetime(2015, 12, 23, 11, 28, 38, 264331)

回答3:

Using NumPy, you can find add or subtract business days using np.busday_offset:

Since 2016-03-27 is a Sunday, rolling forward returns the first valid business day, 2016-03-28:

import numpy as np
np.busday_offset('2016-03-27', 0, roll='forward')
# numpy.datetime64('2016-03-28')

To obtain a datetime object, call item():

np.busday_offset('2016-03-27', 0, roll='forward').item()
# datetime.date(2016, 3, 28)

To advance 5 business days, change the second argument to 5:

np.busday_offset('2016-03-27', 5, roll='forward').item()
# datetime.date(2016, 4, 4)

To go back 5 business days, use a negative offset and roll='backward':

np.busday_offset('2016-03-27', -5, roll='backward').item()
# datetime.date(2016, 3, 18)

np.busday_offset('2016-03-28', -5, roll='backward').item()
# datetime.date(2016, 3, 21)

Here's a calendar for reference:

      March 2016               April 2016         
 Su Mo Tu We Th Fr Sa     Su Mo Tu We Th Fr Sa    
        1  2  3  4  5                     1  2    
  6  7  8  9 10 11 12      3  4  5  6  7  8  9    
 13 14 15 16 17 18 19     10 11 12 13 14 15 16    
 20 21 22 23 24 25 26     17 18 19 20 21 22 23    
 27 28 29 30 31           24 25 26 27 28 29 30

回答4:

If you want to work with a lot of timeseries, have a look at pandas. Adding five business days is quite straightforward:

from datetime import datetime
import pandas as pd

today = datetime.today()
then = today + pd.tseries.offsets.BDay(5)

来源：https://stackoverflow.com/questions/34526240/calculate-date-5-days-from-today-adding-an-extra-day-for-each-day-in-the-next-5

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python

robotframework