蟒蛇：错误类型和指数误差（2.7.6）

Question

我是相当新的蟒蛇，我在2.7.6有一个问题，是不是在3.4.4

的代码有问题：

def answer(population, x, y, strength): 

# make sure Z is infectable 
if population[x][y] > strength: 
    return population 
else: 
    population[x][y] = -1 

# get array dimentions 
rows = len(population) 
cols = len(population[0]) 

# declare checking array 
toCheck = [] 
toCheck.append([x,y]) 

# loop 4 way check 
while(1): 
    #store and pop current element 
    i = toCheck[0][0] 
    j = toCheck[0][1] 
    toCheck.pop(0) 

    # left 
    if j != 0: 
     if population[i][j-1] <= strength and population[i][j-1] != -1: 
      population[i][j-1] = -1 
      toCheck.append([i,j-1]) 

    # top 
    if i != 0: 
     if population[i-1][j] < strength and population[i-1][j] != -1: 
      population[i-1][j] = -1 
      toCheck.append([i-1,j]) 

    # right 
    if j != cols-1: 
     if population[i][j+1] > strength and population[i][j+1] != -1: 
      population[i][j+1] = -1 
      toCheck.append([i,j+1]) 

    # bottom 
    if i != rows-1: 
     if population[i+1][j] > strength and population[i+1][j] != -1: 
      population[i+1][j] = -1 
      toCheck.append([i+1][j]) 

    if len(toCheck) == 0: 
     return population 

给了我一个'TypeError'。虽然代码：

def answer(population, x, y, strength): 

# make sure Z is infectable 
if population[x][y] > strength: 
    return population 
else: 
    population[x][y] = -1 

# get array dimentions 
rows = len(population) 
cols = len(population[0]) 

# declare checking array 
toCheck = [[]] 
toCheck.append([x,y]) 

# loop 4 way check 
while(1): 
    #store and pop current element 
    i = toCheck[0][0] 
    j = toCheck[0][1] 
    toCheck.pop(0) 

    # left 
    if j != 0: 
     if population[i][j-1] <= strength and population[i][j-1] != -1: 
      population[i][j-1] = -1 
      toCheck.append([i,j-1]) 

    # top 
    if i != 0: 
     if population[i-1][j] < strength and population[i-1][j] != -1: 
      population[i-1][j] = -1 
      toCheck.append([i-1,j]) 

    # right 
    if j != cols-1: 
     if population[i][j+1] > strength and population[i][j+1] != -1: 
      population[i][j+1] = -1 
      toCheck.append([i,j+1]) 

    # bottom 
    if i != rows-1: 
     if population[i+1][j] > strength and population[i+1][j] != -1: 
      population[i+1][j] = -1 
      toCheck.append([i+1][j]) 

    if len(toCheck) == 0: 
     return population 

给我和'IndexError'。这两个错误发生在i = toCheck [0] [0]的行。 请帮忙！谢谢。

Answer 1

编辑：此回复是针对问题代码的较早版本。

假设所有的代码应该是放克以内（）：

您需要终止while循环一次toCheck是空的。在您弹出所有值后，原始版本尝试索引空列表。试试这个：

# loop 4 way check 
while len(toCheck) > 0: 
    #store and pop current element 
    i = toCheck[0][0] 
    j = toCheck[0][1] 
    toCheck.pop(0) 

此外，您不需要在添加值之前声明toCheck。您可以更换

toCheck = [[],[]] 
toCheck.append([x,y]) 

随着

toCheck = [x, y]