# Humble Py(thon)

I’ve been doing some Python re-learning. The [specific course](https://edube.org/study/pe2) that I am working my way through starts from the very beginning - a very good place to start. This may feel pointless, but sometimes the material can raise features and concepts that I have forgotten about, or not made the most of. Indeed, this happened today through one of the exercises in this course.

## The Exercise

**“**Write a simple program that calculates the end time after a given number of minutes. The start time is provided as hours (0 to 23) and minutes (0 to 59). For example, if an event begins at 12:17 and lasts for 59 minutes, it will finish at 13:16.**”**

The exercise gave the hint to use the **modulus operator** `%` to solve the problem.

After some time, and some internal debate surrounding the exercise being labeled as **easy**, and a small identity crisis on being a professional software engineer, I arrived at a solution. Easy!

```python
start_hour = int(input("Enter start hour (0-23): "))
start_minute = int(input("Enter start minute (0-59): "))
duration_minutes = int(input("Enter duration in minutes: "))

total_minutes = start_hour * 60 + start_minute + duration_minutes

end_hour = (total_minutes // 60) % 24  
end_minute = total_minutes % 60

print(f"{end_hour}:{end_minute}")
```

## Utility of the Modulus Operator

The modulus operator is not unique to Python; it just so happens that this exercise was done in Python. My new-found respect for this operator resulted in a short investigation into its potential uses. I’ve summarised a few that I came across here:

* **Checking for even or odd numbers**
    
    * `if num % 2 == 0:` (even number)
        
    * `if num % 2 != 0:` (odd number)
        
* **Looping with wraparounds**
    
    * `index = (index + 1) % len(arr)`
        
* **Task scheduling (e.g. do something every 5 iterations)**
    
    * `if iteration % 5 == 0:`
        
* **Divisibility tests (e.g. checking if a number is divisible by 3)**
    
    * `if num % 3 == 0:`
        
* **Extracting digits from a number**
    
    * `last_digit = num % 10`
        

Thanks to this humbling exercise, I am now more aware of this operator and its usefulness. I think this is a good example of how revisiting the basics can be quite helpful. When writing code to solve future problems, I will hopefully recognise and use the modulus operator when appropriate.