Python/financial/interest.py
Turro ea6c6056cf
Added apr_interest function to financial ()
* Added apr_interest function to financial

* Update interest.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update financial/interest.py

* float

---------

Co-authored-by: Christian Clauss <cclauss@me.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
2023-06-19 13:46:29 +02:00

121 lines
3.6 KiB
Python

# https://www.investopedia.com
from __future__ import annotations
def simple_interest(
principal: float, daily_interest_rate: float, days_between_payments: float
) -> float:
"""
>>> simple_interest(18000.0, 0.06, 3)
3240.0
>>> simple_interest(0.5, 0.06, 3)
0.09
>>> simple_interest(18000.0, 0.01, 10)
1800.0
>>> simple_interest(18000.0, 0.0, 3)
0.0
>>> simple_interest(5500.0, 0.01, 100)
5500.0
>>> simple_interest(10000.0, -0.06, 3)
Traceback (most recent call last):
...
ValueError: daily_interest_rate must be >= 0
>>> simple_interest(-10000.0, 0.06, 3)
Traceback (most recent call last):
...
ValueError: principal must be > 0
>>> simple_interest(5500.0, 0.01, -5)
Traceback (most recent call last):
...
ValueError: days_between_payments must be > 0
"""
if days_between_payments <= 0:
raise ValueError("days_between_payments must be > 0")
if daily_interest_rate < 0:
raise ValueError("daily_interest_rate must be >= 0")
if principal <= 0:
raise ValueError("principal must be > 0")
return principal * daily_interest_rate * days_between_payments
def compound_interest(
principal: float,
nominal_annual_interest_rate_percentage: float,
number_of_compounding_periods: float,
) -> float:
"""
>>> compound_interest(10000.0, 0.05, 3)
1576.2500000000014
>>> compound_interest(10000.0, 0.05, 1)
500.00000000000045
>>> compound_interest(0.5, 0.05, 3)
0.07881250000000006
>>> compound_interest(10000.0, 0.06, -4)
Traceback (most recent call last):
...
ValueError: number_of_compounding_periods must be > 0
>>> compound_interest(10000.0, -3.5, 3.0)
Traceback (most recent call last):
...
ValueError: nominal_annual_interest_rate_percentage must be >= 0
>>> compound_interest(-5500.0, 0.01, 5)
Traceback (most recent call last):
...
ValueError: principal must be > 0
"""
if number_of_compounding_periods <= 0:
raise ValueError("number_of_compounding_periods must be > 0")
if nominal_annual_interest_rate_percentage < 0:
raise ValueError("nominal_annual_interest_rate_percentage must be >= 0")
if principal <= 0:
raise ValueError("principal must be > 0")
return principal * (
(1 + nominal_annual_interest_rate_percentage) ** number_of_compounding_periods
- 1
)
def apr_interest(
principal: float,
nominal_annual_percentage_rate: float,
number_of_years: float,
) -> float:
"""
>>> apr_interest(10000.0, 0.05, 3)
1618.223072263547
>>> apr_interest(10000.0, 0.05, 1)
512.6749646744732
>>> apr_interest(0.5, 0.05, 3)
0.08091115361317736
>>> apr_interest(10000.0, 0.06, -4)
Traceback (most recent call last):
...
ValueError: number_of_years must be > 0
>>> apr_interest(10000.0, -3.5, 3.0)
Traceback (most recent call last):
...
ValueError: nominal_annual_percentage_rate must be >= 0
>>> apr_interest(-5500.0, 0.01, 5)
Traceback (most recent call last):
...
ValueError: principal must be > 0
"""
if number_of_years <= 0:
raise ValueError("number_of_years must be > 0")
if nominal_annual_percentage_rate < 0:
raise ValueError("nominal_annual_percentage_rate must be >= 0")
if principal <= 0:
raise ValueError("principal must be > 0")
return compound_interest(
principal, nominal_annual_percentage_rate / 365, number_of_years * 365
)
if __name__ == "__main__":
import doctest
doctest.testmod()