myHealth 1.0

A Python app that helps patients generate simple personal medical history reports for doctor's appointments.

🩺 myHealth

🩺 myHealth is a Python app that helps patients generate simple personal medical history reports for doctor's appointments.

It’s made up of two mini apps:

• 💊 myMedication, which stores key information about the patient's medications, including their purpose, dosage, and dose times; and

• 🫀 myVitals, which tracks the patient’s vital signs.

Click here to watch a video explaining the project.

Click here to view the source code for 🩺 myHealth, the main module. You can run the program with the Linux command python myHealth.py.

The package comes with two csv files, myMedication.csv and myVitals.csv, which contain sample data that you can use to try out 🩺 myHealth. If you'd like to start afresh, you can either delete the files or rename them.

💊 myMedication

Click here to view the source code of the medicine module, where 💊 myMedication is implemented.

Menus & Exceptions

To build menus that are interactive and easy to use, I employed extensive exception handling blocks to deal with invalid selections by users and guide them in navigating the menus.

• The menus in 🩺 myHealth are 'nested', with layered exception handling. This means that 'lower-level' menus will handle some exceptions, and 'bubble' the rest up to 'higher-level' menus where they are handled.

  This makes it easier to redirect the user and stop certain processes when there are 'fatal errors'.

• If processes are stopped prematurely, the data may be damaged. I prevented this by making two copies of the data before every process that manipulates it (adding, editing, removing), a working copy and a backup copy.

  If the process is completed successfully, the manipulated working copy overrides the original; else, the backup copy is returned.

• To ensure that every type of invalid input is mapped to a unique exception, I defined two custom exceptions, DuplicateError and NoSelectionError.

I used ‘match-case’ blocks to redirect users to pages where they can make changes to their medications.

• The available options are displayed using the tabulate library.

• These pages are implemented either as functions or other menus.

Medicine Class

I employed an object-oriented paradigm to represent medications in my program, by defining a Medicine class.

• Each medication is an instance of the class, but exists as a unique object.

• The details of the medications are stored as attributes of their corresponding objects.

• The Medicine class provides several handy methods which guide users in creating and modifying Medicine objects.

File I/O

Let’s look at what happens under the hood when a user interacts with 💊 myMedication.

When the user loads the database, a comma-separated value (csv) file containing information about the medications is converted into a list of Medicine objects with the help of Python’s csv module.

Creating Medicine Objects

1. When the user adds a new medication, a class method of the Medicine class named create prompts the user for its details.

2. Then, it calls the special __init__ constructor method in the background to create a new Medicine object.

Input Validation

💊 myMedication carries out robust input validation using two mechanisms:

1. When a new medication is added, the create class method calls the static methods of the Medicine class to perform checks and re-prompt the user if necessary.

2. When a medication is edited, setter methods are called instead. Since the attributes of the Medicine objects are designated as ‘properties’, they cannot be changed without passing their corresponding setter’s checks. These will raise exceptions when invalid input is detected.

I didn’t rely on the setters earlier when creating new Medicine objects, as it would be impossible to handle multiple exceptions simultaneously and re-prompt the user in a user-friendly manner.

🔧 utility

Click here to view the source code of the utility module, where helper functions are implemented.

Helper Functions & Decorators

To maintain a neat user interface, I used a helper function named clear_and_display to clear the screen whenever a new page is to be displayed.

I abstracted away the screen clearing functionality by implementing it as a decorator. The decorator works by treating the helper function as a ‘first-class object’: it takes the function as an argument, and wraps it with the screen clearing functionality. This made my code more readable, and allowed the functionality to be reused.

🧪 test_medicine

Click here to view the source code of the test_medicine module, where the unit tests for the medicine module are implemented. You can run the tests with Pytest using the Linux command pytest test_medication.py, or with unittest using the Linux command python test_medication.py.

Unit Testing

It is important for my app to be tested in a controlled environment where the states of the Medicine objects are certain. I achieved this using the unittest.mock library, which allowed me to:

• substitute real Medicine objects with mock objects, whose attributes are predetermined.

• The library also allowed me to ‘patch’, that is simulate, real objects, functions, and modules, so that I could create ‘fixtures’, which are predictable behaviors, side effects & return values.

• Moreover, I was able to confirm that my code worked as expected, by ‘asserting’ the number of calls made to the patched functions.

🫀 myVitals

Click here to view the source code of the vitals module, where 🫀 myVitals is implemented.

File I/O

While it also stores data in a csv file, it converts the data into a Pandas DataFrame. This makes it much more convenient to access the data and make changes to it than if a data type native to Python was used.

Input Validation & Regular Expressions

🫀 myVitals also validates user input, but uses regular expressions instead of simple conditionals, which not only makes the code more concise, but also more maintainable as they can be explained by and checked with 3rd party validators such as regexr and regex101.

Binary Search Algorithm & Recursion

Instead of using Panda’s query function or SQL to find records from a particular day or month, I decided to experiment with implementing a binary search algorithm recursively using Pandas and NumPy.

1. 🫀 myVitals calls a function named search_vitals, which checks the record in the middle of the DataFrame. If it is not from the day or month desired, the algorithm disregards all the records that come either before or after it, and repeats the process.

2. Once a match is found, the crawler function is called. It will gather all the records from the same day or month, by checking adjacent records recursively.

Graphing with Matplotlib

Click here to view the source code of the visualisation module, where the graphing is implemented.

To help the patient and their doctor interpret the data conveniently, I used Matplotlib to present the data as beautiful, colourful charts.

Blood Pressure & Pulse Rate

• I plotted line graphs of the patient’s blood pressure and pulse rate in the same figure but on separate axes, so that their trends can be compared.

• The shaded band indicates the patient’s pulse pressure, while the dotted guidelines signal whether the patient’s blood pressure and pulse rate are within healthy limits. These can assist doctors in diagnosing the patient’s risk of heart disease.

Blood Glucose Levels

I chose to present the data on the patient’s blood glucose level in two ways:

1. As a scatterplot, with data points colored according to a colormap.

   To make it easier to monitor the trend, I plotted a line graph of the 3-reading moving average.

   

2. As a histogram, which shows the proportion of readings that are too high, too low, or within the healthy range.

   

Where to Find

If you’d like to download 🩺 myHealth, you can find it on:

• GitHub
• Python Package Index (PYPI)

You can also download it through your command line using the package installer for Python, by executing the following Linux command:

pip install myHealth

The documentation for 🩺 myHealth can be found on ReadtheDocs (in development).