Sched module in Python

# Python program for Creating 
# an event scheduler


import sched
import time


# Creating an instance of the
# scheduler class
scheduler = sched.scheduler(time.time, 
                            time.sleep)

Basic methods available with scheduler instances

• scheduler.enter(): Events can be scheduled to run after a delay, or at a specific time. To schedule them with a delay, enter() method is used.

  Syntax: scheduler.enter(delay, priority, action, argument=(), kwargs={}) Parameters: delay: A number representing the delay time priority: Priority value action: Calling function argument: A tuple of arguments

  Example: Python3 1==

  import sched
  import time
  
  # instance is created
  scheduler = sched.scheduler(time.time,
                              time.sleep)
  
  # function to print time 
  # and name of the event
  def print_event(name):
      print('EVENT:', time.time(), name)
  
  # printing starting time
  print ('START:', time.time())
  
  # first event with delay of
  # 1 second
  e1 = scheduler.enter(1, 1, 
                       print_event, ('1 st', ))
  
  # second event with delay of
  # 2 seconds
  e1 = scheduler.enter(2, 1, 
                       print_event, (' 2nd', ))
  
  # executing the events
  scheduler.run()
  

  Output :

  START: 1580389814.152131
  EVENT: 1580389815.1548214 1 st
  EVENT: 1580389816.1533117  2nd
  

• scheduler.enterabs() The enterabs() time adds an event to the internal queue of the scheduler, as the run() method of a scheduler is called, the entries in the queue of a scheduler are executed one by one.

  Syntax: scheduler.enterabs(time, priority, action, argument=(), kwargs={}) Parameters: time: Time at which the event/action has to be executed priority: The priority of the event action: The function that constitutes an event argument: Positional arguments to the event function kwargs: A dictionary of keyword arguments to the event function

  Example: Python3 1==

  # library imported
  import sched
  import time
  
  # instance is created
  scheduler = sched.scheduler(time.time,
                              time.sleep)
  
  # function to print time and
  # name of the event
  def print_event(name):
      print('EVENT:', time.time(), name)
  
  # printing starting time
  print ('START:', time.time())
  
  # event x with delay of 1 second
  # enters queue using enterabs method
  e_x = scheduler.enterabs(time.time()+1, 1,
                           print_event, 
                           argument = ("Event X", ));
  
  # executing the events
  scheduler.run()
  

  Output :

  START: 1580389960.5845037
  EVENT: 1580389961.5875661 Event X
  

• scheduler.cancel() Remove the event from the queue. If the event is not an event currently in the queue, this method will raise a ValueError.

  Syntax: scheduler.cancel(event) Parameter: event: The event that should be removed.

  Python3 1==

  import sched
  import time
  
  
  # instance is created
  scheduler = sched.scheduler(time.time,
                              time.sleep)
  
  # function to print time and
  # name of the event
  def print_event(name):
      print('EVENT:', time.time(), name)
  
  # printing starting time
  print ('START:', time.time())
  
  # first event with delay 
  # of 1 second
  e1 = scheduler.enter(1, 1, 
                       print_event,
                       ('1 st', ))
  
  
  # second event with delay 
  # of 2 seconds
  e2 = scheduler.enter(2, 1, 
                       print_event,
                       (' 2nd', ))
  
  # removing 1st event from 
  # the event queue
  scheduler.cancel(e1)
  
  # executing the events
  scheduler.run()
  

  Output :

  START: 1580390119.54074
  EVENT: 1580390121.5439944  2nd
  

• scheduler.empty() It return True if the event queue is empty. It takes no argument. Example: Python3 1==

  import sched
  import time
  
  
  # instance is created
  scheduler = sched.scheduler(time.time,
                              time.sleep)
  
  # function to print time 
  # and name of the event
  def print_event(name):
      print('EVENT:', time.time(), name)
  
  # printing starting time
  print ('START:', time.time())
  
  # checking if event queue is
  # empty or not
  print(scheduler.empty())
  
  # event entering into queue
  e1 = scheduler.enter(2, 1,
                       print_event,
                       ('1 st', ))
  
  # checking if event queue is 
  # empty or not
  print(scheduler.empty())
  
  # executing the events
  scheduler.run()
  

  Output :

  START: 1580390318.1343799
  True
  False
  EVENT: 1580390320.136075 1 st
  

• scheduler.queue Read-only attribute returning a list of upcoming events in the order they will be run. Each event is shown as a named tuple with the following fields: time, priority, action, argument, kwargs. Python3 1==

  # library imported
  import sched
  import time
  
  # instance is created
  scheduler = sched.scheduler(time.time,
                              time.sleep)
  
  # function to print time 
  # and name of the event
  def print_event(name):
      print('EVENT:', time.time(), name)
  
  # printing starting time
  print ('START:', time.time())
  
  # event entering into queue
  e1 = scheduler.enter(2, 1,
                       print_event, 
                       ('1 st', ))
  
  # printing the details of
  # upcoming events in event queue
  print(scheduler.queue)
  
  # executing the events
  scheduler.run()
  

START: 1580390446.8743565 [Event(time=1580390448.8743565, priority=1, action=, argument=('1 st', ), kwargs={})] EVENT: 1580390448.876916 1 st