New to Python - Need date calculation help

Python Help
1

This project will determine the following

  1. Is a loan active in a defined period
  2. If a loan is active in a defined period, how many days was it active

Define the Custom Periods

from datetime import datetime, date, timedelta

fy22_p1_start = date(2021, 9, 26)
fy22_p1_end = date(2021, 10, 30)
fy22_p2_start = date(2021, 10, 31)
fy22_p2_end = date(2021, 11, 27)
fy22_p3_start = date(2021, 11, 28)
fy22_p3_end = date(2021, 12, 25)
fy22_p4_start = date(2022, 12, 26)
fy22_p4_end = date(2022, 1, 29)
fy22_p5_start = date(2022, 1, 30)
fy22_p5_end = date(2022, 2, 26)
fy22_p6_start = date(2022, 2, 27)
fy22_p6_end = date(2022, 3, 26)
fy22_p7_start = date(2022, 3, 27)
fy22_p7_end = date(2022, 4, 30)
fy22_p8_start = date(2022, 5, 1)
fy22_p8_end = date(2022, 5, 28)
fy22_p9_start = date(2022, 5, 29)
fy22_p9_end = date(2022, 6, 25)
fy22_p10_start = date(2022, 6, 26)
fy22_p10_end = date(2022, 7, 30)
fy22_p11_start = date(2022, 7, 31)
fy22_p11_end = date(2022, 8, 27)
fy22_p12_start = date(2022, 8, 28)
fy22_p12_end = date(2022, 9, 24)
fy23_p1_start = date(2022, 9, 25)
fy23_p2_end = date(2022, 10, 29)

‘’‘Get input from user about Loan Start and Loan End dates and convert to dates’‘’

loan_start = str(input('Loan Start date(yyyy-mm-dd): '))
loan_start = datetime.strptime(loan_start, '%Y-%m-%d').date()

loan_end = str(input('Loan End date(yyyy-mm-dd): '))
loan_end = datetime.strptime(loan_end, '%Y-%m-%d').date()

print('')
print(f'Period Start Date:',fy22_p7_start)
print(f'Period End Date:',fy22_p7_end)
```print(‘’)``````

‘’‘Determine if Loan is in a specific period’‘’

if loan_start > fy22_p7_end or loan_end < fy22_p7_start:
in_period = ('Loan was not in Period')
print(in_period)
else:
in_period = ('Loan was in Period')
print(in_period)

‘’‘Calculate Days in Period start and end’‘’

if loan_start >= fy22_p7_start:
per_calc_start = loan_start
else:
per_calc_start = fy22_p7_start

if loan_end <= fy22_p7_end:
per_calc_end = loan_end
else:
per_calc_end = fy22_p7_end

‘’‘Calculate Days in Period Days’‘’

period_days = (per_calc_end - per_calc_start)

if period_days > 0:
print(f'Your loan was active for', period_days, 'this period')

    print('Your loan was not active in this period')```

'''Calculate total loan days'''

```days = (loan_end - loan_start)
print(f'Total Loans Days:', days)```

Output

Loan Start date(yyyy-mm-dd):  2022-09-01
Loan End date(yyyy-mm-dd):  2022-09-15

Period Start Date: 2022-03-27
Period End Date: 2022-04-30

Loan was not in Period

Error

TypeError                                 Traceback (most recent call last)
Input In [43], in <cell line: 75>()
     71 '''Calculate Days in Period Days'''
     73 period_days = (per_calc_end - per_calc_start)
---> 75 if period_days > 0:
     76     print(f'Your loan was active for', period_days, 'this period')
     77 else:

TypeError: '>' not supported between instances of 'datetime.timedelta' and 'int'

Can't figure out how to create calculation
2

Please put triple backticks (“code fences”) around your code, it
preserves the indenting (and a lot of other stuff) for others to see.
Eg:

 ```
 your code here
 ```

Fortunately I’m on email and get this stuff raw :slight_smile:

Your issue is that, generally, you cannot compare objects of different
types in Python (because that will usually be nonsensical). So, your
code has:

 '''Calculate Days in Period start and end'''
 if loan_start >= fy22_p7_start:
     per_calc_start = loan_start
 else:
     per_calc_start = fy22_p7_start
 if loan_end <= fy22_p7_end:
     per_calc_end = loan_end
 else:
     per_calc_end = fy22_p7_end

So per_calc_start and per_calc_end are dates.

Then you do this:

 period_days = (per_calc_end - per_calc_start)

so that period_days is now a timedelta, the result of arithmetic
between dates:
https://docs.python.org/3/library/datetime.html#datetime.timedelta

Then you go:

 if period_days > 0:

which raises a TypeError because period_days is a timedelta and
0 is an int. What you want is the number of days the timedelta
represents. Fortunately there’s a .days attribute (see the docs
above), so you could do this:

 if period_days.days > 0:

But I’d actually be inclined to put that in the previous calculation:

 period_days = (per_calc_end - per_calc_start).days
 if period_days > 0:

or to change the variable name:

 period = per_calc_end - per_calc_start
 if period.days > 0:

just to make the meaning of “period” or “period_days” more clear.

Cheers,
Cameron Simpson cs@cskk.id.au

3

Cameron,

Sorry about the formatting, its my first post and I have only started learning Python this week. I really appreciate the help. It worked just like you demonstrated adding the .days.

Thank you so much

4

By Rshypitka via Discussions on Python.org at 12Sep2022 23:17:

Sorry about the formatting, its my first post and I have only started
learning Python this week.

The formatting thing is completely normal, it is not as obvious as it
should be maybe.

Cheers,
Cameron Simpson cs@cskk.id.au