This code will make a full screen window with pygame that you can close with Esc key. At the end you will see the width and height of the screen.
# phisyc.py
import pygame
import sys
pygame.init()
WSIZE = (0, 0)
screen = pygame.display.set_mode(WSIZE)
W, H = screen.get_size()
print(W, H)
clock = pygame.time.Clock()
loop = 1
while loop:
for event in pygame.event.get():
if event.type == pygame.QUIT:
loop = 0
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_ESCAPE:
loop = 0
pygame.display.update()
clock.tick(60)
pygame.quit()
sys.exit()