如何从元素列表中获取班次的开始日期和结束日期

Question

simply what I want if shift == D then I want start date and end date of D, for example in first how many times D appear it 4 times so start date =2021-04-01 and end date = 2021-04-04 that's it same to N also from when N start and end I want just start date, end date and create new dictionary for shift_type leave W but count it also for proper date's I don't understand how do it please check the output that I mentioned

shift_lst = ["D","D","D","D","N","N","W","N","N","D","D","D","D","W","N","N","N"]
current_date = date(2021, 4, 1)
shift_dict=dict()
for shift in (shift_lst):
    if shift == "D":
        shift_type='S1'
        enddate = current_date + timedelta(days=1)
    elif shift == "W":
        enddate = current_date + timedelta(weeks=1)
    elif shift == "N":
        shift_type='S2'
        enddate = current_date


end_date = current_date
shift_dict['shift_type']=shift_type
shift_dict['start_date']=current_date
shift_dict['end_date']=enddate

Expected Output:

{'shift_type' : 'S1','start_date':'2021,4,1','end_date':'2021,4,4'},
{'shift_type' : 'S2','start_date':'2021,4,5','end_date':'2021,4,9'},
{'shift_type' : 'S1','start_date':'2021,4,11','end_date':'2021,4,13'}

Answer 1

So you need to approach the problem like this:

1. create an empty list to store the dicts (a list of dicts).
2. check each element vs the previous (to identify a change).
3. modify the dicts accordingly.

So the code could look like this:

import datetime as dt

shift_lst = ["D","D","D","D","N","N","W","N","N","D","D","D","D","W","N","N","N"]
current_date = dt.date(2021, 4, 1)

list_of_shifts = []

# firt element
if shift_lst[0] == 'D': shift_type = 'S1'
if shift_lst[0] == 'N': shift_type = 'S2'

shift_dict = {'shift_type':shift_type, 'start_date':current_date, 'end_date':current_date}

for i in range(1, len(shift_lst)):

    # check if the shift has changed
    if shift_lst[i] != shift_lst[i-1]:
        # and not a weekend
        if shift_lst[i] == "W":
            pass
        else:
            list_of_shifts.append(shift_dict)
            # start a new dict
            shift_dict={'shift_type':shift_type, 'start_date':current_date, 'end_date':current_date}
    
    if shift_lst[i] == 'D':
        shift_type='S1'
        current_date = current_date + dt.timedelta(days=1)
    elif shift_lst[i] == "W":
        current_date = current_date + dt.timedelta(weeks=1) 
    elif shift_lst[i] == "N":
        shift_type='S2'
        current_date = current_date
    shift_dict["end_date"] = current_date


for i in list_of_shifts:
    print(i)

And the result would be this:

{'shift_type': 'S1', 'start_date': datetime.date(2021, 4, 1), 'end_date': datetime.date(2021, 4, 4)}
{'shift_type': 'S1', 'start_date': datetime.date(2021, 4, 4), 'end_date': datetime.date(2021, 4, 11)}
{'shift_type': 'S2', 'start_date': datetime.date(2021, 4, 11), 'end_date': datetime.date(2021, 4, 11)}
{'shift_type': 'S2', 'start_date': datetime.date(2021, 4, 11), 'end_date': datetime.date(2021, 4, 22)}

You can customise the above to suit your needs...

Answer 2

What if I got "W" first randomly or "L" first (L stands for leave) now see in List shift_lst I got "W" first so leave the "W" or "L" (if L got first) and start from "D" until "N" not come, get start date and end date of "D" like this start_date=2021,4,2 & end_date=2021,4,4 after "D" with "N" when it start on 10th so start_date = 2021,4,10 and end_date = 2021,4,21 so after 2021,4,21 leave "W" and get D Start And end date

• D shift_type = "S1"
• N shift_type = "S2"

    import datetime as dt
    shift_lst = [ "W","D","D","D","L","L","L","L","L","N","N","N","N","N","N","N","N","N","N","N","N","W","D","D","D","D","D","D","W","D"]
    current_date = dt.date(2021, 4, 1)

    list_of_shifts = []
    shift_type=None

    # firt element
    if shift_lst[0] == 'D': shift_type = 'S1'
    if shift_lst[0] == 'N': shift_type = 'S2'

    for i in range(1, len(shift_lst)):

        # check if the shift has changed
    
        if shift_lst[i] != shift_lst[i - 1]:
        # and not a weekend
        if shift_lst[i] == "W":
            pass
        else:
          
            # start a new dict
            list_of_shifts.append(shift_dict)
            shift_dict = {
                'shift_type': shift_type,
                'start_date': current_date,
                'end_date': current_date
            }
          

        if shift_lst[i] == 'D':
            shift_type = 'S1'
            current_date = current_date + dt.timedelta(days=1)
        elif shift_lst[i] == "W":
            current_date = current_date + dt.timedelta(days=1)
        elif shift_lst[i] == "N":
            shift_type = 'S2'
            current_date = current_date
            current_date = current_date + dt.timedelta(days=1)
        shift_dict["end_date"] = current_date


    for i in list_of_shifts:
        print(i)

Expected output

{'shift_type': 'S1', 'start_date': datetime.date(2021, 4, 2), 
'end_date': datetime.date(2021, 4, 4)}
{'shift_type': 'S2', 'start_date': datetime.date(2021, 4, 10), 
'end_date': datetime.date(2021, 4, 21)}
{'shift_type': 'S1', 'start_date': datetime.date(2021, 4, 23), 
'end_date': datetime.date(2021, 4, 27)}
{'shift_type': 'S1', 'start_date': datetime.date(2021, 4, 29), 
'end_date': datetime.date(2021, 4, 29)}