parameterized-mortgage 0.1.5

A simple python package to provide mortgage repayment calculations using the French method of amortization

Parameterized Mortgage

A package to provide an easily vizualizable mortgage class, built on the Holoviz Param and Panel packages.

Installation

Install the package using pip:

pip install parameterized_mortgage

Import the Mortgage class:

from parameterized_mortgage import Mortgage

Demo

The package includes a demo dashboard application to show how the Mortgage class can be embedded in visualizations using holoviz panel. See the code in parameterized_mortgage.dashboard to see how this is achieved.

To run the demo on your own machine, install the package using pipx (install pipx if necessary):

pipx install git+https://github.com/JonathanMair/parameterized_mortgage.git

The run the following command:

dashboard

The panel app will launch and should open automatically in a browser. It will look like this:

Usage

Mortgage class constructor and user-set parameters

The Mortgage constructor takes 3 named parameters:

• principal (float): amount initially borrowed
• rate (float): annual interest rate expressed as a %
• term (int): mortgage term in years

e.g.:

mortgage = Mortgage(principal=300000, rate=4.5, term=20)

These three parameters can be re-set at any time and all other members will be recalculated automatically as a result.

e.g.:

mortgage.rate = 3.8

Other class members

Mortgage.monthly_payment: A float representing the value of monthly repayments without rounding

Mortgage.get_monthly_payment(): Returns the monthly repayment as a string, formatted to 2 decimal places

Mortgage.repayment_schedule(): Returns a pandas DataFrame containing the full repayment schedule or amortization table

Mortgage.annual_summary(): Returns a pandas DataFrame containing the repayment schedule summarized by year

Mortgage.lifetime_summary(): Returns a pandas DataFrame containing the repayment schedule summarized over the whole lifetime of the mortgage

Mortgage.custom_widgets(): Returns dictionary detailing customised widgets for a panel.Param object that will allow the user-set parameters to be incorporated easily in a dashboard

Mortgage.amortization_chart(): Returns a plot of the outstanding loan over time

Mortgage.chart_interest_vs_capital(): Returns a plot of the interest and capital components of monthly payments over time

Contributing

Contributions are welcome!

License

This project is licensed under the GNU GENERAL PUBLIC LICENSE Version 3.

Disclaimer

This software makes calculations that could be relevant to investment decisions, but it is provided without warranty. Users' attention is drawn to the relevant paragraphs of the licence.

Change log

• 0.1.5: updated README.md
• 0.1.4: added script entrypoint
• 0.1.3: moved main.py with demo cli to module dashboard
• 0.1.2: fixed error in param.depends declarations in Mortgage