Dealing with microseconds-CodePudding

I have written this code where I want that code to run exactly at the minute. However, each iteration take few milliseconds and this causes a small delay in my program. Is there a way to where I can subtract these milliseconds just like the way I have subtracted seconds.

import pandas as pd
import datetime as dt
import time

while True:
    now = dt.datetime.now()
    current_time = now.strftime('%Y-%m-%d %H:%M:%S')
    seconds = int(current_time[-2:])
    sleep_sec = 60 - seconds
    time.sleep(sleep_sec)
    print(dt.datetime.now())

This is the output:

OUTPUT IMAGE

As you can see from the output that with each iteration few milliseconds are added to the time. What I want is to print the exact minute where milliseconds is also zero.

CodePudding user response：

using time.time() instead of time.sleep()

import time
import datetime as dt
start_time = time.time()

while True:
    if time.time() - start_time > 60:
        # if 60 seconds pass do something
        print(dt.datetime.now())
        start_time = time.time()
        print("60 seconds passed")

output:

2021-12-24 12:48:30.542806
60 seconds passed
2021-12-24 12:49:30.543792
60 seconds passed
2021-12-24 12:50:30.544508
60 seconds passed
2021-12-24 12:51:30.544826
60 seconds passed
2021-12-24 12:52:30.545028
60 seconds passed
2021-12-24 12:53:30.545661
60 seconds passed
2021-12-24 12:54:30.546452
60 seconds passed

there's still offset, but it's less significant than in your output

CodePudding user response：

time.sleep accepts float if you want to sleep for fractions of seconds. That being said I would not expect python to be able to do exact milisecond precision (there is just way too much happening in your system usually for this level of precision).