Humble Py(thon)
Software engineer at the UK Astronomy Technology Centre, currently developing instrument control software for MOONS, a next-generation spectrograph for the Very Large Telescope (VLT).
I’ve been doing some Python re-learning. The specific course 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!
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.
