Food

Lesson 24 of 41 in Coddy's Make Games with Pygame course.

Food appears in a random cell, never on the snake. Pick a random cell and try again while it lands on the body:

def new_food(body):
    while True:
        cell = (random.randrange(COLS), random.randrange(ROWS))
        if cell not in body:
            return cell

random.randrange(COLS) is a whole number from 0 up to COLS - 1: every column, and never one past the edge. return ends the function, and the loop with it, as soon as a free cell turns up.

cell not in body checks the whole list at once.

Challenge

Easy

Put food on the grid.

Add import random at the top, and new_food(body) as above, below draw_cell.
After direction, set food = new_food(body).
After the fill, draw the food in red (235, 80, 80).

Press Play: a red cell shows somewhere off the snake. Then Check.

Try it yourself

import pygame

CELL = 20
COLS, ROWS = 24, 18
TURNS = {
    pygame.K_LEFT: (-1, 0),
    pygame.K_RIGHT: (1, 0),
    pygame.K_UP: (0, -1),
    pygame.K_DOWN: (0, 1),
}

pygame.init()
screen = pygame.display.set_mode((COLS * CELL, ROWS * CELL))
pygame.display.set_caption("Snake")
clock = pygame.time.Clock()


def draw_cell(cell, color):
    col, row = cell
    pygame.draw.rect(screen, color, (col * CELL + 1, row * CELL + 1, CELL - 2, CELL - 2))


body = [(5, 9), (4, 9), (3, 9)]
direction = (1, 0)

running = True
while running:
    moving = direction
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN and event.key in TURNS:
            turn = TURNS[event.key]
            if turn != (-moving[0], -moving[1]):
                direction = turn

    x = body[0][0] + direction[0]
    y = body[0][1] + direction[1]
    body.insert(0, (x, y))
    body.pop()

    screen.fill((30, 30, 46))
    for cell in body[1:]:
        draw_cell(cell, (120, 220, 120))
    draw_cell(body[0], (180, 255, 160))
    pygame.display.flip()
    clock.tick(10)

pygame.quit()