Digital clock with Python Tkinter

Question

While learning about python tkinter, I decided to make a digital clock:

from datetime import datetime
import tkinter as tk
from threading import Thread
import time
class clock():
 def __init__(self):
 self.display = tk.Tk()
 def start(self):
 def get():
 self.display.geometry("215x62")
 self.display.title("Clock")
 while True:
 try:
 now = datetime.now()
 current_time = now.strftime("%H:%M %p") 
 lbl = tk.Label(self.display, text=str(current_time),
 background = 'black', font = ("Helvetica", 37),
 foreground = 'red')
 lbl.place(x=0, y=0)
 time.sleep(0.1)
 except:
 break
 receive_thread = Thread(target=get)
 receive_thread.start()
 self.display.mainloop()
clock = clock()
clock.start()

Is there any way to make this clock better?

Any comments, answers, or steps in the right direction would be appreciated.

Answer 1

To start, it's crucial that you stop creating a brand new label ten times a second. Just modify the existing one. Also, this is so simple that a class is not called for. Move as much as possible away from your thread, into your setup routine. Finally, your use of %H is likely incorrect given that you also include %p; you probably want %I for a 12-hour clock.

This all suggests:

from datetime import datetime
import tkinter as tk
from threading import Thread
from time import sleep
def main():
 display = tk.Tk()
 display.geometry('215x62')
 display.title('Clock')
 lbl = tk.Label(
 display,
 background='black',
 font=('Helvetica', 37),
 foreground='red',
 )
 lbl.place(x=0, y=0)
 def get():
 while True:
 now = datetime.now()
 lbl.config(text=now.strftime('%I:%M %p'))
 sleep(0.1)
 receive_thread = Thread(target=get)
 receive_thread.start()
 display.mainloop()
if __name__ == '__main__':
 main()

Ten times a second is overkill, and you can safely make this much sleepier. Do not make a thread at all; use an after() timer, and calculate when exactly the clock should tick:

from datetime import datetime
import tkinter as tk
from time import time
def main() -> None:
 display = tk.Tk()
 display.geometry('215x62')
 display.title('Clock')
 lbl = tk.Label(
 display,
 background='black',
 font=('Helvetica', 37),
 foreground='red',
 )
 lbl.place(x=0, y=0)
 def tick() -> None:
 now = datetime.now()
 lbl.config(text=now.strftime('%I:%M %p'))
 until_next = round(
 1000 * (60 - time()%60)
 )
 display.after(ms=until_next, func=tick)
 tick()
 display.mainloop()
if __name__ == '__main__':
 main()

• ARNON: Reiderien always displaying his beautiful codes. 👏🏻👏🏻👏🏻
• Graipher: Won't your second code run into stack size limitations after 1000 seconds, since each invocation of tick starts a new one?
• Reinderien: @Graphier I don't think so. after is asynchronous. It's not going to recurse - this is telling tk to use the event loop and schedule a callback for a later time.