The Mortgage Comparison Tool is an interactive CL python application that allows user to calculate mortgage information such as monthly payments, lifetime interest on a loan, amortization schedules, and the effect of overpayments after inputing some basic mortgage information. User are allowed to save mortgages that they create for the session.
The goal of this Mortgage Comparison tool is to allow the user an easy way to compare mortgages whether they are looking to purchase a home, refinance a home, or want to make overpayments on an existing loan.
- As a user, I want an easy way to view, compare, and manipulate potential mortgage scenarios to inform future financial decisions or goals.
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- User looking to purchase a home and wants to compare different mortgages by percentage rate, loan length, lifetime interest, and monthly payment.
- User looking to refinance a home and wanting to compare current loan data with new potential loans by loan length, monthly payment, and overall cost of the loan.
- User wanting to add a loan for comparison.
- User wanting to compare how monthly payments affects their loan.
- User wanting to compare how a lump principal affects their loan.
- User wanting to save loans they want to keep for comparison.
- User wanting to see the amortization schedule of a loan that they have entered.
This project utilizes Object Oriented Programming and centers around one main class, Mortgage.
The majority of the calculations are done via methods on that Mortgage class.
Created in draw.io, the following flowchart provides a visualization of the planning process for this application. During the development of the application, it became apparent that additional inputs, functionality, and outputs were required for the implementation for some of the calculations required and to better organise the options in a way that made sense to the user.
An example of this additional development is for principal overpayments. Originally, I had them as separate options. But based on initial user testing and feedback, I decided to combine them in the same menu option and allowing the user to select which type of overpayment they would make. This helped the organise the menu in a more logical way to the user.
Application Flowcart
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The user is prompted to input basic mortgage details as well as an amount for the extra monthly payments. This input is then used to calculate a Mortgage profile and prints both the profile and an amortization schedule based on the new calculations. The user is given the option to save this mortgage to their mortgages when the calculations are completed.
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The user is prompted to input basic mortgage details as well as an amount for the lump payment to be applied to the Principal balance. This input is then used to calculate a Mortgage profile and prints both the original profile inputed and then an updated Mortgage profile. The user is given the option to save this updated mortgage to their mortgages when the calculations are completed.
- For future development, I wanted to implement a table of data analysis of the aggregate mortgage data inputed by users to provide insight into the type of mortgages that user want to compare. Examples of potential insights would be average mortgage principal amount, average length of the mortgage, and average APR.
- I noticed that other students implemented custom heroku terminal shell for deployment. I thought this was interesting and would like to implement this should I have more time to develop this further.
- At the moment, the user is limited to 10 characters when naming their mortgage. This limit could be raised, but I would need additional time to ensure that that the printed output would be limited to a certain character length so that it doesn't not disrupt the layout of the comparison table.
- During testing, it was revealed that when users save Mortgage profiles after applying Extra Monthly Principal payments, the mortgage profile that is saved is based on the original Mortgage inputs and is not updated with the new loan length and lifetime interest on the loan. For a future feature, I would like to be able to recalculate the updated length of the loan and the lifetime loan interest. With these updated values, users could then save this updated mortgage profile into their session to use to compare against other saved mortgages.
- Python3
- GitHub - used to save and store all the files for this website
- GitPod and VSCode - was used as the IDE to develop and test the code for this website in both the cloud and locally.
- Git - provided the version control
- Heroku - provided the cloud deployment environment shell and Command Line Interface (CLI)
- Google Docs - used for notes and documentation
- Google Sheets - provided the spreadsheet application for storing the data generated by user inputs
- draw.io - used for flowchart creation
- PEP8 Code Institute Python Linter - tested the validity of python code (https://pep8ci.herokuapp.com/)
The following libraries in this program.
- Colorama - producing colored terminal text
- pyfiglet - takes ASCII text and renders it in ASCII art fonts
- Tabulate - displays lists in a table
- Termcolor - Allows printing in color
- gspread - Python API for Google Sheets.
- googleauth - Google authentication library for Python
GitHub and Heroku was used to deploy this website using the Gitpod Code Institute template which preloads any required dependencies. The following steps were taken:
- Log into GitHub account.
- Navigate to the project repository: [Memory-game]((https://github.com/hysinh/mortgage-comparison-tool)
- Navigate to the CODE link on the navigation across the top.
- Then, navigate to the green CODE button on the right side and click.
- Select the Local tab and click on the copy icon to make a copy of the repository.
- Log into Heroku.com account.
- Navigate to the "New" button on the top right.
- Click on "New" and then click on "Create a new app".
- On the next page, create a unique App name for your deployment and choose a region. Then, click on the "Create app" button.
- Once your app has been created, it directs you to a new screen.
- Navigate across the top of the screen and click on the "Settings" tab.
- Navigate down the page and click on the "Reveal Config Vars" button.
- For the first key, type in "CREDS" and then copy and paste the entirety of the creds.json file into the value box.
- For the second key, type in "PORT" and then type in "8000" in its corresponding value.
- Under Buildpacks, add the python buildpack first. Then, add the nodejs buildpack. The buildpacks must be added in that order.
- After this is complete, navigate to the Deploy tab from the menu across the top of the page. Click on "GitHub" under Deployment method and provide the required access when prompted.
- Choose Automatic or Manual deployment.
- Click "Deploy" when ready to deploy.
- Open the Mortgage-Comparison-tool repository on GitHub.
- Navigate to the CODE link on the navigation across the top.
- Then, navigate to the green CODE button on the right side and click.
- Select the Local tab and click on the copy icon to make a copy of the repository.
- Then navigate back to your main GitHub dashboard and then create a new repository with your desired name.
- On the next page, navigate to the bottom of the page and select Import code under "Import code from another repository".
- In the next window, paste the copied link of the Memory-game repository into the line.
- Then, click Begin Import to import the repository code.
- Make changes and/or deploy as desired.
- This program requires the use of a Google sheets file with a Google Drive and Google Sheets API to setup as is.
This application was developed with Python3. No HTML, CSS, or Javascript was used.
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I used the Code Institute PEP8 Python Linter for code validation.
Python Validation
Manual testing was performed on the website checking for print errors, content errors, and any errors in the flow of the application or in it's calculations.
- Microsoft Edge
- Google Chrome
- Opera
| Page | Test | Pass/Fail |
|---|---|---|
| Intro/Logo | Does the Logo page load and allow the user to progress to the Main Menu? | Pass |
| Main Menu | Does the Main menu display correctly | Pass |
| Main Menu | Is the input validation for the Main Menu working correctly? | Pass |
| Main Menu | If the user selects an option from the Main Menu, does it direct the user to that option correctly? | Pass |
| Add Mortgage | On the Add Mortgage page, does it allow the user to create a Mortgage profile? | Pass |
| Add Mortgage | Is the input validation on the Add Mortgage page working? | Pass |
| Add Mortgage | Is a Mortgage profile added correctly if the user selects this option? | Pass |
| Add Mortgage | Is the Google Sheet updated with the data of the new Mortgage profile created regardless of whether the Mortgage profile is saved for the session? | Pass |
| Add Mortgage | Once Add Mortgage options are completed, is the user directed back to the Main Menu options? | Pass |
| View Mortgage | Does the page display an error message if there are no saved Mortgage profiles and directed back to the Main Menu? | Pass |
| View Mortgage | Does the page display all of the saved Mortgage Profiles and their name to the user? | Pass |
| View Mortgage | Is the user able to select a Mortgage Profile to view? | Pass |
| View Mortgage | Does an error message display if the user enters an invalid Mortgage option? | Pass |
| View Mortgage | Does the page display all of the saved Mortgage Profiles and their name to the user? | Pass |
| View Mortgage | When the user enters a valid Mortgage option, is the Mortgage profile displayed on the terminal? | Pass |
| View Mortgage | Is the user able to view another Mortgage and is given the option to exit this page and return to Main Menu? | Pass |
| Compare Mortgages | Does the page display an error message if there are less than 2 Mortgage profiles saved and directed back to the Main Menu? | Pass |
| Compare Mortgages | Does the page display all of the saved Mortgage Profiles and their name to the user? | Pass |
| Compare Mortgages | If there are 2 or more saved Mortgage profiles saved, does a comparison table print to the terminal? | Pass |
| Compare Mortgages | Is the user directed back to the Main Menu after the comparison table display is completed? | Pass |
| Overpayments | Is the user given an option to explore Extra Monthly Principal payments or Lump Principal Payments? | Pass |
| Overpayments | Is the user given an error message if they choose an invalid option? | Pass |
| Overpayments | Is the user able to exit the menu and return to the Main Menu? | Pass |
| Extra Monthly Principal Overpayments | Is the user able to enter Mortgage profile with extra monthly principal payments? | Pass |
| Extra Monthly Principal Overpayments | Are all user inputs validated with an error message printed? | Pass |
| Extra Monthly Principal Overpayments | Once the data is accepted, is the Mortgage profile displayed with an updated Amortization schedule? | Pass |
| Extra Monthly Principal Overpayments | Is the user able to save their Mortgage profile if desired? Does a confirmation display | Pass |
| Extra Monthly Principal Overpayments | Is the user redirected to the Main menu? | Pass |
| Extra Lump Overpayments | Is the user able to enter Mortgage profile with extra monthly principal payments? | Pass |
| Extra Lump Overpayments | Are all user inputs validated with an error message printed? | Pass |
| Extra Lump Overpayments | Once the data is accepted, is the Mortgage profile displayed with an updated Amortization schedule? | Pass |
| Extra Lump Overpayments | Is the user able to save their Mortgage profile if desired? Does a confirmation display | Pass |
| Extra Lump Overpayments | Is the user redirected to the Main menu? | Pass |
| Amortization Schedule | Does the page display an error message if there are no saved Mortgage profiles and directed back to the Main Menu? | Pass |
| Amortization Schedule | Does the page display all of the saved Mortgage Profiles and their name to the user? | Pass |
| Amortization Schedule | Is the user able to select a Mortgage Profile to amortize? | Pass |
| Amortization Schedule | Does an error message display if the user enters an invalid Mortgage option? | Pass |
| Amortization Schedule | Does an amortization schedule print for the selected Mortgage Profile | Pass |
| Amortization Schedule | Is the user able to view another Mortgage and is given the option to exit this page and return to Main Menu? | Pass |
| Exit Program | Does the terminal clear and an exit message print when this option is selected? | Pass |
| 0 Menu Option | Does the terminal clear and the Main menu print with a prompted to input a Menu option? | Pass |
| Bug | Page | Fix |
|---|---|---|
| Confirmation message for saved mortgage option not printing to terminal after saving a mortgage | Extra Monthly Principal Payments | Removed code that ends loop to resolve. |
| Confirmation message for saved mortgage option not printing to terminal after saving a mortgage | Extra Lump Principal Payments | Removed code that ends loop to resolve. |
| Unclear for users what to do if Main Menu is no longer visible. | All Pages | Add text above menu prompt that instructs user to enter 0 to go to the Main menu. |
| Table needs to display Mortgage name rather than Mortgage key | Compare Mortgages | Updates Mortgage class method that generates values for comparison table so that mortgage name displays instead of mortgage ID/key |
| Table needs to display Mortgage name rather than Mortgage key | Amortization Schedule | Replace print statement with mortgage name variable rather than Mortgage key |
| Unexpected indentation | Main Menu Prompt | Removes backslash from string |
- Although I have included a function that clears the terminal, I noticed that anything above the terminal screen does not clear and is still available to view if you scroll up. This is potentially confusing but I was not able to resolve it. My mentor said that it is common for older terminals to push content upward and not truly clear the screen.
- When viewed through a mobile device, the terminal goes off screen. I will need to research this to see if this is something that is resolvable.
| Bug | Line | Unresolved Reason |
|---|---|---|
| Line length | 111 | I tried several different places to attempt to break up the lines to stay <79 but it resulted in poor print outcomes. |
| Line length | 121 | I tried to delete the extra spaces in the formula but it caused "missing white space around operator" errors. |
- ASCII Art https://stackoverflow.com/questions/9632995/how-to-easily-print-ascii-art-text
- https://pypi.org/project/pyfiglet/
- http://www.figlet.org/examples.html
- Clearing the console https://stackoverflow.com/questions/517970/how-can-i-clear-the-interpreter-console
- Input validation https://www.copahost.com/blog/input-python/#:~:text=For%20example%2C%20if%20you%20want,%22)
- Mortgage calculator formulas https://en.wikipedia.org/wiki/Mortgage_calculator,
- Mortgage calculator https://www.ccpc.ie/consumers/money-tools/extra-mortgage-payments-calculator/
- Mortgage calculator https://www.ccpc.ie/consumers/money-tools/mortgage-calculator/
- https://automatetheboringstuff.com/2e/chapter8/
- Python dictionaries https://www.codecademy.com/learn/dscp-python-fundamentals/modules/dscp-python-dictionaries/cheatsheet
- Python dictionaries https://www.freecodecamp.org/news/add-to-dict-in-python/
- Python dictionaries https://www.w3schools.com/python/python_dictionaries_nested.asp
- Python dictionaries https://www.digitalocean.com/community/tutorials/python-add-to-dictionary
- Tabulate https://pypi.org/project/tabulate/
- Amoritization https://www.investopedia.com/terms/a/amortization.asp
- Amoritization https://discuss.python.org/t/calculation-of-mortgage-amortization/20687/3
- Amoritization https://sidhanthk9.medium.com/how-to-code-an-amortization-schedule-in-python-e2d2b417c61a
- Color https://pypi.org/project/termcolor/ https://sparkbyexamples.com/pandas/print-pandas-dataframe-without-index/#:~:text=Use%20hide_index(),Python%203.7%20or%20the%20latest.
- https://stackoverflow.com/questions/517970/how-can-i-clear-the-interpreter-console
- https://www.geeksforgeeks.org/clear-screen-python/
- W3Schools Python https://www.w3schools.com/python
- https://www.python.org/