Why does this function not work properly?

Question

I can't understand why the auto_clock() function can work properly but the clock_time_add() function. The first function would print out a column of lists from 1, 2, 3, ...which is expected while the second would just print out a column of zeros.

This is output of the first function: enter image description here

And this is the output of the second one: enter image description here

And here is the code:

import time
def auto_clock():
 second, minute, hour, day = -1, 0, 0, 1
 while True:
 second += 1
 time.sleep(1) 
 if second == 60:
 second = 0
 minute += 1 
 if minute == 60:
 minute = 0
 hour += 1
 if hour == 24:
 hour = 0
 day += 1
 time_clock = [day, hour, minute, second]
 return time_clock
def clock_time_add():
 while True: 
 time_clock = auto_clock()
 print(time_clock)
clock_time_add()

• arshovon: What is the expected output?
• Devin Clark: @arsho The second function's output is supposed to be the first function's output.
• Klaus D.: You should also be aware that sleep(1) will not sleep exactly one second and in combination with time it takes to run the code there might be a drift in your clock rather quickly if you run it in a loop.

Answer 1

In the second function, you are not passing updated values after one second. That is why, the first function is being called with the same second, minute, hour, and day value.

I have updated the code to pass the updated value to the first function.

import time
def auto_clock(second, minute, hour, day):
 second += 1
 if second == 60:
 second = 0
 minute += 1
 if minute == 60:
 minute = 0
 hour += 1
 if hour == 24:
 hour = 0
 day += 1
 return second, minute, hour, day
def clock_time_add():
 second, minute, hour, day = 0, 0, 0, 1
 while True:
 second, minute, hour, day = auto_clock(second, minute, hour, day)
 print([day, hour, minute, second])
 time.sleep(1)
clock_time_add()

Output for first 100 records:

[1, 0, 0, 1]
[1, 0, 0, 2]
[1, 0, 0, 3]
[1, 0, 0, 4]
[1, 0, 0, 5]
[1, 0, 0, 6]
[1, 0, 0, 7]
[1, 0, 0, 8]
[1, 0, 0, 9]
[1, 0, 0, 10]
[1, 0, 0, 11]
[1, 0, 0, 12]
[1, 0, 0, 13]
[1, 0, 0, 14]
[1, 0, 0, 15]
[1, 0, 0, 16]
[1, 0, 0, 17]
[1, 0, 0, 18]
[1, 0, 0, 19]
[1, 0, 0, 20]
[1, 0, 0, 21]
[1, 0, 0, 22]
[1, 0, 0, 23]
[1, 0, 0, 24]
[1, 0, 0, 25]
[1, 0, 0, 26]
[1, 0, 0, 27]
[1, 0, 0, 28]
[1, 0, 0, 29]
[1, 0, 0, 30]
[1, 0, 0, 31]
[1, 0, 0, 32]
[1, 0, 0, 33]
[1, 0, 0, 34]
[1, 0, 0, 35]
[1, 0, 0, 36]
[1, 0, 0, 37]
[1, 0, 0, 38]
[1, 0, 0, 39]
[1, 0, 0, 40]
[1, 0, 0, 41]
[1, 0, 0, 42]
[1, 0, 0, 43]
[1, 0, 0, 44]
[1, 0, 0, 45]
[1, 0, 0, 46]
[1, 0, 0, 47]
[1, 0, 0, 48]
[1, 0, 0, 49]
[1, 0, 0, 50]
[1, 0, 0, 51]
[1, 0, 0, 52]
[1, 0, 0, 53]
[1, 0, 0, 54]
[1, 0, 0, 55]
[1, 0, 0, 56]
[1, 0, 0, 57]
[1, 0, 0, 58]
[1, 0, 0, 59]
[1, 0, 1, 0]
[1, 0, 1, 1]
[1, 0, 1, 2]
[1, 0, 1, 3]
[1, 0, 1, 4]
[1, 0, 1, 5]
[1, 0, 1, 6]
[1, 0, 1, 7]
[1, 0, 1, 8]
[1, 0, 1, 9]
[1, 0, 1, 10]
[1, 0, 1, 11]
[1, 0, 1, 12]
[1, 0, 1, 13]
[1, 0, 1, 14]
[1, 0, 1, 15]
[1, 0, 1, 16]
[1, 0, 1, 17]
[1, 0, 1, 18]
[1, 0, 1, 19]
[1, 0, 1, 20]
[1, 0, 1, 21]
[1, 0, 1, 22]
[1, 0, 1, 23]
[1, 0, 1, 24]
[1, 0, 1, 25]
[1, 0, 1, 26]
[1, 0, 1, 27]
[1, 0, 1, 28]
[1, 0, 1, 29]
[1, 0, 1, 30]
[1, 0, 1, 31]
[1, 0, 1, 32]
[1, 0, 1, 33]
[1, 0, 1, 34]
[1, 0, 1, 35]
[1, 0, 1, 36]
[1, 0, 1, 37]
[1, 0, 1, 38]
[1, 0, 1, 39]
[1, 0, 1, 40]

Answer 2

Consider that the while loop in your first function has no purpose, as the return time_clock means it will exit on its first iteration. Indentation is critical in Python.

In time_clock_add you're calling auto_clock over and over with a single iteration, with the same starting point, so the same thing will be printed each time.