Revenue accrual

accrual_v1.py

import pandas as pd
from pandas.tseries.offsets import MonthEnd

def assign_to_months(start_date:pd.Timestamp, end_date:pd.Timestamp, total:float, year:int) -> pd.Series:
        """
        start_date: start date of the contract
        end_date: end date of the contract
        total: total amount of the contract
        year: year to be accrued, everything outside this year will not be accrued
        """
        n_of_days = (end_date - start_date) / pd.Timedelta(1, 'days')
        
        try:
            daily = total / n_of_days 
        except:
            daily = -1 #Add this to flag errors in contract dates. Any negative number must be checked.
        
        months = [i for i in range(1,13)]
        month_dict = dict.fromkeys(months, 0)  
        
        for p in pd.period_range(start_date, end_date, freq='D'):
            if p.year == year:
                month_dict[p.month] += 1
        
        for k in month_dict.keys():
            if (end_date.month == k) & (end_date.year == year):
                month_dict[k] = max(0,(month_dict[k] * daily) - daily)
            else:
                month_dict[k] = (month_dict[k] * daily)
                
        return pd.Series([round(v,2) for v in month_dict.values()], index=[f'{year}-{m}' for m in months])

#Usage
df = pd.DataFrame({'start_date':[pd.Timestamp('2020-01-10')], 'end_date': [pd.Timestamp('2020-02-20')], 'total': [10]})
df.apply(lambda x: assign_to_months(x['start_date'], x['end_date'], x['total'], 2020), axis=1)