I'm trying to make conway game of life but something happening

Question

edit: i made a huge mistake in the qeustion don't bother trying to help.

I'm trying but when ever run the code, I get a window that I can draw on but when i run (which i set the button to key pad enter) the simulation, it get rid of all the cell. code:

import pygame,sys,math

from pygame.constants import USEREVENT

pygame.init()

srceen_size = (900,900)
srceen = pygame.display.set_mode(srceen_size)
pygame.display.set_caption("conway game of life")
clock = pygame.time.Clock()

def D_list(list):
    list2 = []
    for i in list:
        if i not in list2:
            list2.append(i)
    return list2

fps = 120
chuck = (320,320)
cell = []
cell_color = (120, 120, 139)
cell_size = 18
cell_delete = False
movement = USEREVENT
cell_create = False
cell_moving = False
cell_re = False
list_dumbie = []
index1 = 0
index4 = 0
gen = []
index2 = 0
index3 = 0
new_gen = []
celless = True

pygame.time.set_timer(movement, 3000)
while True:
    clock.tick(fps)
    if cell_create == True:
        pos_mouse = pygame.mouse.get_pos()
        x,y = pos_mouse
        X = x % 20
        Y = y % 20
        index2 = index2 + 1
        x, y = x - X, y - Y
        cell.append((x,y))
        cell = D_list(cell)
        cell.sort()
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                sys.exit()
            if event.key == pygame.K_KP_ENTER:
                if cell_moving == True:
                    cell_moving = False
                else:
                    cell_moving = True
            if event.key == pygame.K_LSHIFT:
                if cell_re == False:
                    cell_re = True
                if cell_re == True:
                    cell_re = False
        if event.type == pygame.MOUSEBUTTONDOWN:
            if cell_re == False:
                cell_create = True
                cell_delete = False
            if cell_re == True:
                cell_create = False
                cell_delete = True
        if event.type == pygame.MOUSEBUTTONUP:
            if cell_create == True:
                cell_create = False
            if cell_delete == True:
                cell_delete = False
        if event.type == movement: #this is where i had problem
            if cell_moving == True:
                for a in cell:
                    list_dumbie = cell
                    list_dumbie.pop(index1)
                    for b in list_dumbie:
                        if b[0] == a[0] - cell_size or b[0] == a[0] + cell_size:
                            if b[1] == a[1] - cell_size or b[1] == a[1] + cell_size:
                                index4 = index4 + 1
                        if index4 == 3 or index4 == 4:
                            new_gen.append(a)
                    index4 = 0


                    index1 = index1 + 1
                cell = new_gen
                new_gen = []
                cell.sort()
                index1 = 0
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LSHIFT:
                cell_re = False
    srceen.fill((22, 22, 22))
    for x,y in cell:
        pygame.draw.rect(srceen,cell_color,(x+1,y+1,cell_size,cell_size))
    pygame.display.update()

also conway game of life is a cellular automata. there only two rules

1. a cell stay alive if there 3 or 4 cell next to it and if more or less cell are next to the cell, the cell die
2. if a dead cell surrounded by 3 living cell, the dead cell come alive.

Answer 1

First you have to count the neighbours of the cells. Create a grid that shows whether a cell is alive and a second grid where you count the neighbors of each living cell. Based on the data from these 2 girdes, you can implement the rules and make a new list of living cells:

while True:
    # [...]

    for event in pygame.event.get():
        # [...]

        if event.type == movement:
            if cell_moving == True:

                alive = [[False] * 45 for _ in range(45)]
                ncount = [[0] * 45 for _ in range(45)]
                for a in cell:
                    i, j = a[0] // 20, a[1] // 20
                    alive[j][i] = True
                    for k, l in [(-1, -1), (0, -1), (1, -1), (-1, 0), (1, 0), (-1, 1), (0, 1), (1, 1)]:
                        if 0 <= i+k < 45 and 0 <= j+l < 45:
                            ncount[j+l][i+k] += 1

                new_gen = []
                for i in range(45):
                    for j in range(45):
                        x, y = i * 20, j * 20

                        if alive[j][i] and (ncount[j][i] == 2 or ncount[j][i] == 3):
                            new_gen.append((x, y))

                        elif not alive[j][i] and ncount[j][i] == 3:
                            new_gen.append((x, y))
                
                cell = new_gen
                cell.sort()