python game of life

import random
import time
import os

#---------------------------------------------------------------------------

def initGrid(cols, rows, array):
    for i in range(rows):
        arrayRow = []
        for j in range(cols):
            if (i == 0 or j == 0 or (i == rows - 1) or (j == cols - 1)):
                arrayRow += [-1]
            else:
                ran = random.randint(0,3)
                if ran == 0:
                    arrayRow += [1]
                else:
                    arrayRow += [0]
        array += [arrayRow]

#---------------------------------------------------------------------------

def printGen(cols, rows, array, genNo):
    os.system("cls")

    print("Game of Life -- Generation " + str(genNo + 1))

    for i in range(rows):
        for j in range(cols):
            if array[i][j] == -1:
                print("#", end=" ")
            elif array[i][j] == 1:
                print(".", end=" ")
            else:
                print(" ", end=" ")
        print("\n")

#---------------------------------------------------------------------------

def processNextGen(cols, rows, cur, nxt):
    for i in range(1,rows-1):
        for j in range(1,cols-1):
            nxt[i][j] = processNeighbours(i, j, cur)

#---------------------------------------------------------------------------

def processNeighbours(x, y, array):
    nCount = 0
    for j in range(y-1,y+2):
        for i in range(x-1,x+2):
            if not(i == x and j == y):
                if array[i][j] != -1:
                    nCount += array[i][j]
    if array[x][y] == 1 and nCount < 2:
        return 0
    if array[x][y] == 1 and nCount > 3:
        return 0
    if array[x][y] == 0 and nCount == 3:
        return 1
    else:
        return array[x][y]

#---------------------------------------------------------------------------
############################################################################
#---------------------------------------------------------------------------

ROWS = 11
COLS = 39
GENERATIONS = 100
DELAY = 0.2

thisGen = []
nextGen = []

initGrid(COLS, ROWS, thisGen)
initGrid(COLS, ROWS, nextGen)

for gens in range(GENERATIONS):
    printGen(COLS, ROWS, thisGen, gens)
    processNextGen(COLS, ROWS, thisGen, nextGen)
    time.sleep(DELAY)
    thisGen, nextGen = nextGen, thisGen
input("Finished. Press <return> to quit.")# python game of life