Conway's Game of Life

Conway's game of life

import pygame, sys
from pygame.locals import *
FPS = 4

csize = 10
wwidth = int(input("Enter width of the table: "))*csize
wheight = int(input("Enter size of the table: "))*csize


cwidth = wwidth / csize
cheight = wheight / csize

blk =    (0,  0,  0)
wht =    (255,255,255)
dgray = (40, 40, 40)
grn =    (0,255,0)


def drawGrid():
    for x in range(0, wwidth, csize):
        pygame.draw.line(dispsurf, dgray, (x,0),(x,wheight))
    for y in range (0, wheight, csize):
        pygame.draw.line(dispsurf, dgray, (0,y), (wwidth, y))

def colourGrid(item, mainDict):
    x = item[0]
    y = item[1]
    y = y * csize
    x = x * csize 
    if mainDict[item] == 0:
        pygame.draw.rect(dispsurf, wht, (x, y, csize, csize))
    if mainDict[item] == 1:
        pygame.draw.rect(dispsurf, grn, (x, y, csize, csize))
    return None

def blankGrid():
    gridDict = {}
    for y in range (int(cheight)):
        for x in range (int(cwidth)):
            gridDict[x,y] = 0
    return gridDict

def startinggridinput(mainDict):
    count = 0
    mainkeys = sorted(mainDict, key = lambda x:(x[0],x[1]))
    for each in range(int(cheight)):
        inp = input("Enter a full row(0 for dead and 1 for live cell): ")
        for eac in inp:
            mainDict[mainkeys[count]] = int(eac)
            count+=1

    return mainDict

def getneighb(item,mainDict):
    neighb = 0
    for x in range (-1,2):
        for y in range (-1,2):
            check = (item[0]+x,item[1]+y)
            if check[0] < cwidth  and check[0] >=0:
                if check [1] < cheight and check[1]>= 0:
                    if mainDict[check] == 1:
                        if x == 0 and y == 0:
                            neighb += 0
                        else:
                            neighb += 1
    return neighb

def tick(mainDict):
    nTick = {}
    for item in mainDict:
        numberneighb = getneighb(item, mainDict)
        if mainDict[item] == 1:
            if numberneighb < 2:
                nTick[item] = 0
            elif numberneighb > 3:
                nTick[item] = 0
            else:
                nTick[item] = 1
        elif mainDict[item] == 0:
            if numberneighb == 3:
                nTick[item] = 1
            else:
                nTick[item] = 0
    return nTick

def main():
    pygame.init()
    global dispsurf
    FPSCLOCK = pygame.time.Clock()
    dispsurf = pygame.display.set_mode((wwidth,wheight))
    pygame.display.set_caption('Game of Life')
    dispsurf.fill(wht)
    mainDict = blankGrid() 
    mainDict = startinggridinput(mainDict)
    for item in mainDict:
        colourGrid(item, mainDict)
    drawGrid()
    pygame.display.update()
    while True:
        for event in pygame.event.get():
            if event.type == QUIT:
                pygame.quit()
                sys.exit()
        mainDict = tick(mainDict)
        for item in mainDict:
            colourGrid(item, mainDict)
        drawGrid()
        pygame.display.update()    
        FPSCLOCK.tick(FPS)   
main()