Debounce (Python)
How to create and use a debouncer in Python.
In both of these examples, the inner function won't run until at least DEBOUNCE_TIME seconds has passed.
Standalone
from threading import Timer
import time
DEBOUNCE_TIME = 1 # 1 second
debounced_action = None
def debounce_action(message: str) -> None:
""" Print the last message to be invoked within a certain amount of time """
global debounced_action
def print_message():
print(message)
if debounced_action:
debounced_action.cancel()
debounced_action = Timer(DEBOUNCE_TIME, print_message)
debounced_action.start()
if __name__ == "__main__":
debounce_action("Won't print this one")
time.sleep(.5)
debounce_action("Or this one")
time.sleep(.99)
debounce_action("This one will though!")
The benefit of using this standalone is that you can have multiple items debouncing with the same inner function and different parameters by using a dict to store the different debounced_actions instead of using a singular global.
Decorator
from threading import Timer
import time
DEBOUNCE_TIME = 1
def debounce(wait):
""" Decorator that will postpone a functions
execution until after wait seconds
have elapsed since the last time it was invoked. """
def decorator(fn):
def debounced(*args, **kwargs):
def call_it():
fn(*args, **kwargs)
try:
debounced.t.cancel()
except(AttributeError):
pass
debounced.t = Timer(wait, call_it)
debounced.t.start()
return debounced
return decorator
@debounce(DEBOUNCE_TIME)
def print_message(message: str):
print(message)
if __name__ == "__main__":
print_message("Won't print this one")
time.sleep(.5)
print_message("Or this one")
time.sleep(.99)
print_message("This one will though!")
The benefit of using a decorator is you can throw it on any function that needs debouncing at it saves you the reuse of the debouncing code in multiple places.
References:
Last modified: 202401040446