Based on my testing, this is because threads can only be started once, and as the timer relies on a thread, the timer can only be started once. This means that the only way to re-start the timer would be to do:
def newTimer():
global t
t = Timer(10.0,api_call)
newTimer()
instead of the t = Timer part, and do
t.cancel()
newTimer()
t.start()
instead of the current re-start code.
This makes your full code:
from threading import Timer
def api_call():
print("Call that there api")
def newTimer():
global t
t = Timer(10.0,api_call)
newTimer()
def my_callback(channel):
if something_true:
print('reset timer and start again')
t.cancel()
newTimer()
t.start()
print("\n timer started")
elif something_else_true:
t.cancel()
print("timer canceled")
else:
t.cancel()
print('cancel timer for sure')
try:
if outside_input_that_can_happen_a_lot:
my_callback()
finally:
#cleanup objects
Hope this helps.
Answer from CrazySqueak on Stack OverflowGitHub
gist.github.com › aeroaks › ac4dbed9c184607a330c
Reset Timer in Python · GitHub
Reset Timer in Python. GitHub Gist: instantly share code, notes, and snippets.
Top answer 1 of 2
8
Based on my testing, this is because threads can only be started once, and as the timer relies on a thread, the timer can only be started once. This means that the only way to re-start the timer would be to do:
def newTimer():
global t
t = Timer(10.0,api_call)
newTimer()
instead of the t = Timer part, and do
t.cancel()
newTimer()
t.start()
instead of the current re-start code.
This makes your full code:
from threading import Timer
def api_call():
print("Call that there api")
def newTimer():
global t
t = Timer(10.0,api_call)
newTimer()
def my_callback(channel):
if something_true:
print('reset timer and start again')
t.cancel()
newTimer()
t.start()
print("\n timer started")
elif something_else_true:
t.cancel()
print("timer canceled")
else:
t.cancel()
print('cancel timer for sure')
try:
if outside_input_that_can_happen_a_lot:
my_callback()
finally:
#cleanup objects
Hope this helps.
2 of 2
0
Here is a small class which does exactly that from CrazySqueak's answer. So please upvote his answer not mine!
import threading
class AdvTimer():
def __init__(self, interval, callback):
self.interval = interval
self.callback = callback
def restart(self):
self.timer.cancel()
self.start()
def start(self):
self.timer = threading.Timer(self.interval, self.callback)
self.timer.start()
Python: Run code every n seconds and restart timer on condition - Stack Overflow
After 15 mins of no movement I ... and restart the time. ... The description sounds similar to a dead main's switch / watchdog timer. How it is implemented depends on your application: whether there is an event loop, are there blocking functions, do you need a separate process for proper isolation, etc. If no function is blocking in your code: #!/usr/bin/env python3 import time ... More on stackoverflow.com
Created My First Tkinter Project: Count-Down Timer : Reset/pause and resume buttons.
pause = "No" an option is to use paused = False which is more pythonic. Glad you are having fun More on reddit.com
10
52
March 20, 2023How do I stop a function and restart it when it is called again?
You can make a generator function that yields a result, and you call next every time you want the next iteration. These are functions that are designed to continue where you left off each time you ask for the next iteration. https://realpython.com/introduction-to-python-generators/ mini-example from that article: def multi_yield(): yield_str = "This will print the first string" yield yield_str yield_str = "This will print the second string" yield yield_str multi_obj = multi_yield() print(next(multi_obj)) #This will print the first string print(next(multi_obj)) #This will print the second string print(next(multi_obj)) # raises the StopIteration exception More on reddit.com
3
7
August 18, 2021while loop - A timer that restarts on a trigger Python - how to restart? - Stack Overflow
Bit of a newbie so bear with: I am trying to make a crude 60s timer that is reset and starts again on the rising edge of a trigger (ie when a gate goes high). The problem I have is that it won't re... More on stackoverflow.com
Videos
Top answer 1 of 2
10
Here is a corrected version:
from __future__ import print_function
from threading import Timer
def hello():
print("Hello World!")
class RepeatingTimer(object):
def __init__(self, interval, f, *args, **kwargs):
self.interval = interval
self.f = f
self.args = args
self.kwargs = kwargs
self.timer = None
def callback(self):
self.f(*self.args, **self.kwargs)
self.start()
def cancel(self):
self.timer.cancel()
def start(self):
self.timer = Timer(self.interval, self.callback)
self.timer.start()
t = RepeatingTimer(3, hello)
t.start()
Example Run:
$ python -i foo.py
>>> Hello World!
>>> Hello World!
>>> t.cancel()
2 of 2
2
The reason your timer is not restarting is because you never reset self.interval to True before trying to restart the timer. However, if that's the only change you make, you will find your timer is vulnerable to a race condition that will result in more than one timer running concurrently.
ActiveState
code.activestate.com › recipes › 577407-resettable-timer-class-a-little-enhancement-from-p
Resettable Timer class (a little enhancement from python builtin Timer class) « Python recipes « ActiveState Code
A more simple resettable timer class, by adding few logic from python builtin Timer code.
PyPI
pypi.org › project › resettabletimer
Client Challenge
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ProgramCreek
programcreek.com › python › example › 2317 › threading.Timer
Python Examples of threading.Timer
def start(self, instance, fields=None, restore=None, send_update=None): """ Starts a threading.Timer chain, to repeatedly update a resource instances's expirationTime. @param instance: resource instance @param fields: additional fields mandatory during update @param restore: function that will ...
Raspberry Pi Forums
forums.raspberrypi.com › board index › programming › python
A resetable background timer? - Raspberry Pi Forums
Possibly SIGALRM will do what you want. There's documentation and an example at http://docs.python.org/2/library/signal.html.
Top answer 1 of 5
3
You could probably accomplish it with threading really elegantly but if you need a quick fix you could try
import time
timer = 15 * 60 # 60 seconds times 15 mins
while timer > 0:
time.sleep(0.985) # don't sleep for a full second or else you'll be off
timer -= 1
if someCondition:
timer = 15 * 60
executeCode() # called when time is zero and while loop is exited
2 of 5
1
If the whole process is as simple as you say, I would go about it like this (semi-psuedo-code):
def run_every_fifteen_minutes():
pass
def should_reset_timer():
pass
def main():
timer = 0
while True:
time.sleep(1)
timer+=1
if should_reset_timer():
timer = 0
if timer == 15*60:
run_every_fifteen_minutes()
timer = 0
Note that this won't be exactly fifteen minutes in. It might be late by a few seconds. The sleep isn't guaranteed to sleep only 1 second and the rest of the loop will take some time, too. You could add a system time compare in there if you need it to be really accurate.
Python
mail.python.org › pipermail › tutor › 2012-November › 092767.html
[Tutor] Reusing Timers (threading.timer)
November 14, 2012 - > > if autoUpdates is enabled > get updateFrequency > start timer with time value from updateFrequency > when time is reached, run update method > else > cancel timer Well that won't work, because once the update has run, it will stop checking for new updates.
GitHub
gist.github.com › alexbw › 1187132
A repeating timer in Python · GitHub
September 1, 2011 - def __init__(self, function, interval, *args, **kwargs): super(RepeatingTimer, self).__init__() self.args = args self.kwargs = kwargs self.function = function self.interval = interval def start(self): self.callback() def stop(self): self.interval = False def callback(self): if self.interval: self.function(*self.args, **self.kwargs) Timer(self.interval, self.callback, ).start()
Reddit
reddit.com › r/learnpython › created my first tkinter project: count-down timer : reset/pause and resume buttons.
r/learnpython on Reddit: Created My First Tkinter Project: Count-Down Timer : Reset/pause and resume buttons.
March 20, 2023 -
Been learning functions and how to add them to buttons and working with time in general. So wanted to create a little project that will test me on those areas.
import tkinter as tk
from tkinter import *
import time
root = Tk()
root.title(' COUNT-DOWN TIMER')
#root.geometry("800x400")
root['background']='#2F4F4F'
total_time = 0
rest = 0
pause = "No"
#####ADD/MINUS/RESET FUNCTIONS
def add_time_hour():
global total_time
total_time += 3600
countdown_label.config(text=f"{total_time//3600:02}:{(total_time//60)%60:02}:{total_time%60:02}",fg = '#00FF00',font=("Arial", 24))
def add_time_min():
global total_time
total_time += 60
countdown_label.config(text=f"{total_time//3600:02}:{(total_time//60)%60:02}:{total_time%60:02}",fg= "#00FF00",font=("Arial", 24))
def add_time_sec():
global total_time
total_time += 1
countdown_label.config(text=f"{total_time//3600:02}:{(total_time//60)%60:02}:{total_time%60:02}",fg= "#00FF00",font=("Arial", 24))
def add_rest_min():
global rest
rest += 60
rest_label.config(text=f"{(rest // 3600) % 3600:02}:{(rest // 60) % 60:02}:{rest % 60:02}",fg= "#00FF00",font=("Arial", 24))
def reset():
global total_time, rest,pause
pause = "No"
total_time = 0
rest = 0
countdown_label.config(text=f"{total_time//3600:02}:{(total_time//60)%60:02}:{total_time%60:02}",fg= "#00FF00",font=("Arial", 24))
rest_label.config(text=f"{(rest // 3600) % 3600:02}:{(rest // 60) % 60:02}:{rest % 60:02}",fg= "#00FF00",font=("Arial", 24))
############TIME FUNCTIONS#############################################
def countdown():
global total_time,rest, pause
if total_time > 0 and pause == "No":
total_time -= 1
countdown_label.config(text=f"{(total_time // 3600) % 3600:02}:{(total_time // 60) % 60:02}:{total_time % 60:02}",fg="#00FF00", font=("Arial", 24))
root.after(1000,countdown)
if total_time == 0:
countdown_label.config(
text=f"{(total_time // 3600) % 3600:02}:{(total_time // 60) % 60:02}:{total_time % 60:02}", fg="red",
font=("Arial", 24))
elif total_time == 0 and rest > 0 and pause == "No":
rest -= 1
rest_label.config(text=f"{(rest// 3600) % 3600:02}:{(rest // 60) % 60:02}:{rest % 60:02}", fg="#00FF00", font=("Arial", 24))
root.after(1000,countdown)
if rest == 0:
rest_label.config(text=f"{(rest // 3600) % 3600:02}:{(rest // 60) % 60:02}:{rest % 60:02}", fg="red",
font=("Arial", 24))
def countdown_pause():
global pause
pause = "Yes"
def countdown_unpause():
global pause
pause = "No"
countdown()
#############LABELS####################
countdown_label = tk.Label(text = "00:00:00",fg="#00FF00",bg='#2F4F4F', font=("Arial", 24))
countdown_label.grid(row= 0, column = 2, columnspan=2)
countdown_label_title = tk.Label(text = "RUNNING: ",fg="#00FF00",bg='#2F4F4F', font=("Arial", 24))
countdown_label_title.grid(row= 0, column = 0, columnspan=2)
rest_label = tk.Label(text = "00:00:00", fg= "#00FF00",bg='#2F4F4F',font=("Arial", 24))
rest_label.grid(row= 1, column = 2, columnspan=2)
rest_label_title = tk.Label(text = "RESTING: ",fg="#00FF00",bg='#2F4F4F', font=("Arial", 24))
rest_label_title.grid(row= 1, column = 0, columnspan= 2)
#BUTTONS###
add_button = tk.Button(root, text="START", command=countdown, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 3, column = 1)
add_button = tk.Button(root, text="+HOUR", command=add_time_hour, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 2, column = 0)
add_button = tk.Button(root, text="+MNTS", command=add_time_min, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 2, column = 1)
add_button = tk.Button(root, text="+SCND", command=add_time_sec, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 2, column = 2)
add_button = tk.Button(root, text="RESET ", command=reset, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 3, column = 0)
add_button = tk.Button(root, text="RST-MIN", command=add_rest_min, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 2, column = 3)
add_button = tk.Button(root, text="PAUSE", command=countdown_pause, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 3, column = 2)
add_button = tk.Button(root, text="RESUME", command=countdown_unpause, bg='#36648B', font=("Arial", 18))
add_button.grid(row= 3, column = 3)
root.mainloop() Top answer 1 of 4
15
pause = "No" an option is to use paused = False which is more pythonic. Glad you are having fun
2 of 4
5
You don't need the command: from tkinter import * Stay away from global imports and global variables whenever possible. Also I'd use ttk instead: from tkinter import ttk And then: button = ttk.Button(root....) ttk.Style().configure('TButton', font = ('Helvetica', 20, 'bold')) That way all your buttons will have the same style without you having to define them each time you instance them.
Reddit
reddit.com › r/learnpython › how do i stop a function and restart it when it is called again?
r/learnpython on Reddit: How do I stop a function and restart it when it is called again?
August 18, 2021 -
I've searched around the internet and I can't seem to find an answer. I have a series of checkboxes that when clicked, calls a function that is a countdown timer. If I wait for the timer to end, and click another checkbox, it works fine. But if I check a second box while the other is still running, it starts another timer so then I have 2 timers running... or 3 or 4 depending on how many checkboxes I click. If I click another checkbox while the timer is still running, how do I get it to stop the first timer and start over?
def countdown(count): import beepy label['text'] = count if count >= 0: root.after(1000, countdown, count - 1) else: beepy.beep(4) label['text'] = 0
each checkbox has this code to call the countdown function:
ttk.Checkbutton(routine, command=lambda: countdown(45))
Top answer 1 of 2
5
You can make a generator function that yields a result, and you call next every time you want the next iteration. These are functions that are designed to continue where you left off each time you ask for the next iteration. https://realpython.com/introduction-to-python-generators/ mini-example from that article: def multi_yield(): yield_str = "This will print the first string" yield yield_str yield_str = "This will print the second string" yield yield_str multi_obj = multi_yield() print(next(multi_obj)) #This will print the first string print(next(multi_obj)) #This will print the second string print(next(multi_obj)) # raises the StopIteration exception
2 of 2
3
If you remember the id returned by after, you can use after_cancel to cancel the scheduled call: id = None def countdown(count, new=True): global id if new and id is not None: root.after_cancel(id) id = None label['text'] = count if count >= 0: id = root.after(1000, countdown, count - 1, False) else: id = None beepy.beep(4) label['text'] = 0 It'd be better practice to wrap this in a class to get rid of the global variable, but there you go.
Real Python
realpython.com › python-timer
Python Timer Functions: Three Ways to Monitor Your Code – Real Python
December 8, 2024 - In this step-by-step tutorial, you'll learn how to use Python timer functions to monitor how quickly your programs are running. You'll use classes, context managers, and decorators to measure your program's running time. You'll also learn the benefits of each method and which to use given the ...
Top answer 1 of 3
1
Try this:
import time
import keyboard
x=60
while True:
try:
if keyboard.is_pressed('space'):
x=60
print(f"Timer reset to {x}")
elif keyboard.is_pressed('space'):
break
else:
print(f"{x} seconds left")
time.sleep(1)
x-=1
except Exception:
pass
2 of 3
1
This is my suggestion. The problem is, that time.sleep is blocking, so when it's sleeping you cannot break it by pressing escape. You will have to spam the escape button, but it works.
import keyboard
import time
t=60
last = False
current = False
while True:
current = keyboard.is_pressed('space') # triggered when space bar is pressed
if last == 0 and current == 1:
while t>=0:
if keyboard.is_pressed('escape'):
t = 60
last = False
current = False
print("Timer stopped.")
break
print(t)
t-=1
time.sleep(1)
last = current # reset
Sample output/test:
60
59
58
57
56
60
59
58
57
56
60
59
60
59
58
Python Pool
pythonpool.com › home › blog › understanding the python timer class with examples
Understanding the Python Timer Class with Examples - Python Pool
May 23, 2021 - You can export this class as a module and install it as a dependency in your code. Then by using a single line, you can import it – · import time class Timer: """ Timer class """ def __init__(self): self.start = time.time() ''' Restarts the timer.
Stack Overflow
stackoverflow.com › questions › 64259270 › how-to-start-timer-and-reset-it-back-in-python
How to start timer and reset it back in python? - Stack Overflow
October 8, 2020 - otherwise start timer afresh print('restart_timer') if self.start_event.is_set(): self.reset_event.set() print('restart_timer:reset') else: self.start_event.set() print('restart_timer:start') def terminate(self): print('terminate') self.terminate_event.set() class Application(Tk): def show_idle_screen(self): for widget in self.winfo_children(): widget.destroy() # Create new widget element def show_product_info(self, barcodeno): # call web api and get response # create information widget element # -Timer(5.0, self.show_idle_screen).start() tmr = TimerThread(timeout, sleep_chunk, Application().s
Super Fast Python
superfastpython.com › home › tutorials › how to restart a thread in python
How to Restart a Thread in Python - Super Fast Python
September 11, 2022 - Tying this together, the complete example of simulating a thread restart with a new instance is listed below. Running the example first creates the thread and runs it as before. The main thread joins the new thread until it terminates. The main thread then creates a new thread instance with the same configuration, starts it, and joins it. As we expect, this new thread executes without incident. Overwhelmed by the python concurrency APIs?
Top answer 1 of 16
152
The best way is to start the timer thread once. Inside your timer thread you'd code the following
class MyThread(Thread):
def __init__(self, event):
Thread.__init__(self)
self.stopped = event
def run(self):
while not self.stopped.wait(0.5):
print("my thread")
# call a function
In the code that started the timer, you can then set the stopped event to stop the timer.
stopFlag = Event()
thread = MyThread(stopFlag)
thread.start()
# this will stop the timer
stopFlag.set()
2 of 16
76
Improving a little on Hans Then's answer, we can just subclass the Timer function. The following becomes our entire "repeat timer" code, and it can be used as a drop-in replacement for threading.Timer with all the same arguments:
from threading import Timer
class RepeatTimer(Timer):
def run(self):
while not self.finished.wait(self.interval):
self.function(*self.args, **self.kwargs)
Usage example:
def dummyfn(msg="foo"):
print(msg)
timer = RepeatTimer(1, dummyfn)
timer.start()
time.sleep(5)
timer.cancel()
produces the following output:
foo
foo
foo
foo
and
timer = RepeatTimer(1, dummyfn, args=("bar",))
timer.start()
time.sleep(5)
timer.cancel()
produces
bar
bar
bar
bar
Raspberry Pi Forums
forums.raspberrypi.com › board index › programming › python
Tkinter inactivity reset timer - Raspberry Pi Forums
I wanted to spin up some sort of ... if the timer reaches 0 the screen would reset back to my main screen for inactivity. I was looking in python at after(), but not sure how I would reset it if the user strikes a key. Also, if they do finish and move to the next screen I need to restart the countdown ...