Run certain code every n seconds

Question

Is there a way to  for example  print Hello World  every n seconds  For example  the program would go through whatever code I had  then once it had been 5 seconds  with time sleep    it would execute that code  I would be using this to update a file though  not print Hello World   For example   startrepeat  print  Hello World      01    Repeats print  Hello World   ever  01 seconds  for i in range 5       print i    gt  gt  Hello World   gt  gt  0  gt  gt  1  gt  gt  2  gt  gt  Hello World   gt  gt  3  gt  gt  Hello World   gt  gt  4

User · Answer

Here is a simple example compatible with APScheduler 3.00+:

# note that there are many other schedulers available
from apscheduler.schedulers.background import BackgroundScheduler

sched = BackgroundScheduler()

def some_job():
    print('Every 10 seconds')

# seconds can be replaced with minutes, hours, or days
sched.add_job(some_job, 'interval', seconds=10)
sched.start()

...

sched.shutdown()

Alternatively, you can use the following. Unlike many of the alternatives, this timer will execute the desired code every n seconds exactly (irrespective of the time it takes for the code to execute). So this is a great option if you cannot afford any drift.

import time
from threading import Event, Thread

class RepeatedTimer:

    """Repeat `function` every `interval` seconds."""

    def __init__(self, interval, function, *args, **kwargs):
        self.interval = interval
        self.function = function
        self.args = args
        self.kwargs = kwargs
        self.start = time.time()
        self.event = Event()
        self.thread = Thread(target=self._target)
        self.thread.start()

    def _target(self):
        while not self.event.wait(self._time):
            self.function(*self.args, **self.kwargs)

    @property
    def _time(self):
        return self.interval - ((time.time() - self.start) % self.interval)

    def stop(self):
        self.event.set()
        self.thread.join()


# start timer
timer = RepeatedTimer(10, print, 'Hello world')

# stop timer
timer.stop()

User · Answer

My humble take on the subject  a generalization of Alex Martelli s answer  with start   and stop   control   from threading import Timer  class RepeatedTimer object       def   init   self  interval  function   args    kwargs           self  timer       None         self interval     interval         self function     function         self args         args         self kwargs       kwargs         self is running   False         self start        def  run self           self is running   False         self start           self function  self args    self kwargs       def start self           if not self is running              self  timer   Timer self interval  self  run              self  timer start               self is running   True      def stop self           self  timer cancel           self is running   False   Usage   from time import sleep  def hello name       print  Hello  s     name  print  starting     rt   RepeatedTimer 1  hello   World     it auto-starts  no need of rt start   try      sleep 5    your long-running job goes here    finally      rt stop     better in a try finally block to make sure the program ends    Features    Standard library only  no external dependencies start   and stop   are safe to call multiple times even if the timer has already started stopped function to be called can have positional and named arguments You can change interval anytime  it will be effective after next run  Same for args  kwargs and even function

User · Answer

Save yourself a schizophrenic episode and use the Advanced Python scheduler      http   pythonhosted org APScheduler  The code is so simple   from apscheduler scheduler import Scheduler  sched   Scheduler   sched start    def some job        print  Every 10 seconds   sched add interval job some job  seconds   10        sched shutdown

User · Answer

Here s a version that doesn t create a new thread every n seconds   from threading import Event  Thread  def call repeatedly interval  func   args       stopped   Event       def loop            while not stopped wait interval     the first call is in  interval  secs             func  args      Thread target loop  start           return stopped set   The event is used to stop the repetitions   cancel future calls   call repeatedly 5  print   Hello  World     do something else here    cancel future calls     stop future calls   See Improve current implementation of a setInterval python

User · Answer

import threading  def printit      threading Timer 5 0  printit  start     print  Hello  World    printit      continue with the rest of your code   https   docs python org 3 library threading html timer-objects

User · Answer

You can start a separate thread whose sole duty is to count for 5 seconds  update the file  repeat  You wouldn t want this separate thread to interfere with your main thread

User · Answer

def update        import time     while True          print  Hello World           time sleep 5    That ll run as a function  The while True  makes it run forever  You can always take it out of the function if you need

[python] Run certain code every n seconds

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