Python：从熊猫的周数和年份计算一周的开始日期和结束日期

Question

I have created the following table with the code

 newdf['Year_Date'] = pd.DatetimeIndex(newdf['AbsenceBegDate']).year
 newdf['Week_Number'] = pd.DatetimeIndex(newdf['AbsenceBegDate']).week
 newdf.drop('AbsenceBegDate', axis=1, inplace=True)

newdf:

Emp_ID        Year_Date       Week_Number        Salary         Hours_Worked
5500            2019              30              300              30
3300            2019              31              350              31
3300            2019              32              400              35

I need to add two columns Start Date and End Date of that week from the week number and year

For example,

Emp_ID        Year_Date       Week_Number        Salary         Hours_Worked     Start_Date      End_Date
5500            2019              30              300              30            07/25/2019        07/31/2019
3300            2019              31              350              31             08/01/2019       08/07/2019
3300            2019              32              400              35            08/08/2019        08/15/2019

Can you tell me how to extract this start date and end date. your help is appreciated

Answer 1

You could create a function to do this: first define where to start. Here is for instance what you would do to have today as starting date and you can of course adapt it to your own needs:

today    = date.today()
Week     = today.isocalendar()[1]
pastWeek = Week-1
year     = 2020

and then define this function:

def get_dates(year, week):
     d = date(year,1,1)
     if(d.weekday()<= 3):
         d = d - timedelta(d.weekday())             
     else:
         d = d + timedelta(7-d.weekday())
     dlt = timedelta(days = (week-1)*7)
     return d + dlt,  d + dlt + timedelta(days=6)

Having done that:

X = get_dates(year, (pastWeek-1) )

which gives you enough info to do the job:

Startdate       = str(X[0])
Enddate         = str(X[1])
StartdateNew    = pd.to_datetime(Startdate).date()
EnddateNew      = pd.to_datetime(Enddate).date()
StartdateNew2   = StartdateNew.strftime('%Y%m%d') 
EnddateNew2     = EnddateNew.strftime('%Y%m%d')