How to make "player health" decrease when it collides with an enemy sprite in pygame

Question

I made a surface for the player health and drew it on the screen. Then I made an if statement checking to see if the player X position was == to the enemy X position and if it was the player health would continuously decrease. I know it was decreasing because I was having it print out the player health afterwards in the console and everything was good but the health on the screen would not change. What am I doing wrong? I am a newbie at pygame and a beginner in python therefore my code is not written in the best way...

Sorry the code is very long but the # should show everything...

import pygame
from sys import exit
from time import sleep
pygame.init()

clock = pygame.time.Clock()

screen = pygame.display.set_mode((1200, 535))
background = pygame.image.load("background1.jpg")
background = pygame.transform.rotozoom(background, 0, 2)

# Player
player_surf = pygame.image.load("player_sprites/player_right.png").convert_alpha()
player_rect = player_surf.get_rect(bottomright = (575, 470))
player_surf = pygame.transform.rotozoom(player_surf, 0, 2.5).convert_alpha()

# Health...
health = 50
health_font = pygame.font.Font('Pixeltype.ttf', 50)
health_display = health_font.render(f"Health {health}", True, (0, 0, 0))

# Enemy #1
enemy1_surf = pygame.image.load("enemy1sprites/enemy1_right.png").convert_alpha()
enemy1_rect = enemy1_surf.get_rect(bottomleft = (1100, 462))
enemy1_surf = pygame.transform.rotozoom(enemy1_surf, 0, 2.5).convert_alpha()

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()

    screen.blit(background, (0, 0))
    screen.blit(player_surf, player_rect)
    screen.blit(enemy1_surf, enemy1_rect)
    screen.blit(health_display, (550, 75))

    # Player Movement
    if event.type == pygame.KEYDOWN:
        if event.key == pygame.K_LEFT:
            player_surf = pygame.image.load("player_sprites/player_left.png")
            player_surf = pygame.transform.rotozoom(player_surf, 0, 2.5)
            player_rect.x -= 4
        if event.key == pygame.K_RIGHT:
            player_surf = pygame.image.load("player_sprites/player_right.png")
            player_surf = pygame.transform.rotozoom(player_surf, 0, 2.5)
            player_rect.x += 4
        if player_rect.x >= 1075:
            player_rect.x = 1075
        elif player_rect.x <= 0:
            player_rect.x = 0
    wave_one = True
    # Enemy 1 AI
    if player_rect.x != enemy1_rect.x:
        if player_rect.x > enemy1_rect.x:
            enemy1_surf = pygame.image.load("enemy1sprites/enemy1_right.png")
            enemy1_surf = pygame.transform.rotozoom(enemy1_surf, 0, 2.5)
            enemy1_rect.x += 1
        elif player_rect.x < enemy1_rect.x:
            enemy1_surf = pygame.image.load("enemy1sprites/enemy1_left.png")
            enemy1_surf = pygame.transform.rotozoom(enemy1_surf, 0, 2.5)
            enemy1_rect.x -= 1
            
    # Collision with enemy
    if player_rect.x == enemy1_rect.x:
        health -= 0.005
        print(health)

    pygame.display.update()
    clock.tick(60)

I expected it to continuously update the health_display but It did not.

Answer 1

Have you tried updating / re-rendering the text on screen? From your code, it appears that the health is only printed when updated, not shown in the game.