save project

snake.py

 import pygame
 from pygame import locals
+import random
 
 # 初始化pygame，为使用硬件做准备
 pygame.init()
@@ -59,8 +60,8 @@ while True:
         num2 = random.randint(1, 16)
         apple_x = num1 * 30 - 30
         apple_y = num2 * 30 - 30
-
-    position.pop(0)
+    else:
+        position.pop(0)
     # 将背景图画上去
     screen.blit(background, (0, 0))
     # 将贪吃蛇的头画上去