Exercise: Converting seconds – Hands-on Computer Science

Download as a script python-exercise-seconds.py with the task as comments, to run in VS Code or Positron

Task

Write a function format_duration(seconds) that gets a number of seconds and returns a text that expresses the same duration in hours, minutes and seconds, for example "2 h 5 min 7 s" for 7507 seconds. The function itself prints nothing; it returns the text with return. A main program main asks for the seconds, calls the function and prints the result.

What it should look like

How many seconds? 7507
7507 seconds are 2 h 5 min 7 s.

Your program

def main():
    answer = input("How many seconds? ")
    seconds = int(answer)
    duration = format_duration(seconds)
    print(f"{seconds} seconds are {duration}.")


def format_duration(seconds):
    # Work out hours, minutes and seconds and return the text.
    return ""


main()

Because format_duration returns its result, you can also test it on its own. To do so, temporarily replace the last line with print(format_duration(7507)) and compare with the expected result.

SHOW HINT 1

An hour has 3600 seconds. seconds // 3600 gives the full hours, and seconds % 3600 the seconds left over after that. With this remainder you do the same once more with 60 for the minutes.

SHOW HINT 2

Test your function with values whose result you know by heart: 59 seconds, 60 seconds, 3600 seconds and 3661 seconds.

SHOW THE SOLUTION

def main():
    answer = input("How many seconds? ")
    seconds = int(answer)
    duration = format_duration(seconds)
    print(f"{seconds} seconds are {duration}.")


def format_duration(seconds):
    hours = seconds // 3600
    rest = seconds % 3600
    minutes = rest // 60
    rest = rest % 60
    return f"{hours} h {minutes} min {rest} s"


main()

The function splits the seconds in two steps, first into hours and a remainder, then the remainder into minutes and seconds. For 7507 that gives 2 hours and a remainder of 307 seconds, and 307 seconds are 5 minutes and 7 seconds.

For the quick ones

Extend the function with days, so that 90061 seconds appear as 1 d 1 h 1 min 1 s.