How do I correctly format a target time for a countdown?

Right now I'm trying to e开发者_运维百科nter a time in 24 hour format and initiate a countdown from the current time to the specified time.

So currently the user is entering a target hour and a target minute. I'm not sure what to do with these values to begin a countdown from now until the specified time.

import datetime

now = datetime.datetime.now() # gets the time now, puts it in now

expiringHour = int(input("What hour does the meter expire? Enter 0-23 "))

if expiringHour < 0:
    print("Error. Enter a correct value")
if expiringHour > 23:
    print("Error. Enter a correct value")

expiringMinute = int(input("What minute does the meter expire? Enter 0-59 "))

if expiringMinute < 0:
    print("Error. Enter a correct value")
if expiringMinute > 59:
    print("Error. Enter a correct value")

print(expiringHour, expiringMinute)

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Well, you convert the values to a datetime, and then eneter a loop where display the remaining time from now to the expiring minute, and then sleep for a while, and then display it again, until it reaches zero.

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Actually, the correct answer to this involves creating a datetime.datetime object and incrementing the datetime.datetime object till we reach the finish time.

But since you said you wanted a GUI, I had used python wrapper over xdaliclock on Ubuntu to have a countdown timer. Yeah, this is not applicable if you are on a system where xdaliclock is not available.