Skip to content

Added apr_interest function to financial #6025

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 5 commits into from
Jun 19, 2023
Merged
Changes from 3 commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
37 changes: 37 additions & 0 deletions financial/interest.py
Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,43 @@ def compound_interest(
)


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

Expand Down