值错误：无法解包的值太多（预期为3）

时间：2018-08-06 13:37:30

标签： python python-3.x tuples artificial-intelligence valueerror

我正在尝试实现值迭代算法。 我有一个网格

grid = [[0, 0, 0, +1],
    [0, "W", 0, -1],
    [0, 0, 0, 0]]

动作列表

actlist = {UP:1, DOWN:2, LEFT:3, RIGHT:4}

还有奖励功能

reward = [[0, 0, 0, 0],
      [0, 0, 0, 0],
      [0, 0, 0,  0]]

我编写了一个函数T，该函数返回3个元组的元组。

def T(i,j,actions):
if(i == 0 and j == 0):
    if(actions == UP):
        return (i,i,0.8),(i,i,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i+1,j,0.8),(i,j,0.1),(i,j+1,0.1)
    elif(actions == LEFT):
        return (i,j,0.8),(i,j,0.1),(i+1,j,0.1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i,i,0.1),(i+1,j,0.1)
elif (i == 0 and j == 1):
    if(actions == UP):
        return (i,i,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == LEFT):
        return (i,j-1,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i,j,0.1),(i,j,0.1)
elif(i == 0 and j == 2):
    if(actions == UP):
        return (i,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return(i+1,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == LEFT):
        return (i,j-1,0.8),(i,j,0.1),(i+1,j,0.1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i,j,0.1),(i+1,j,0.1)
elif(i == 0 and j == 3):
    if(actions == UP):
        return (-1,-1,0.8),(-1,-1,0.1),(-1,-1,0.1)
    elif(actions == DOWN):
        return (-1,-1,0.8),(-1,-1,0.1),(-1,-1,0.1)
    elif(actions == LEFT):
        return (-1,-1,0.8),(-1,-1,0.1),(-1,-1,0.1)
    elif(actions == RIGHT):
        return (-1,-1,0.8),(-1,-1,0.1),(-1,-1,0.1)
# 2nd row
elif (i == 1 and j == 0):
    if(actions == UP):
        return (i-1,j,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == DOWN):
        return (i+1,j,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == LEFT):
        return (i,j,0.8),(i-1,j,0.1),(i+1,j,0.1)
    elif(actions == RIGHT):
        return (i,j,0.8),(i-1,j,0.1),(i+1,j,0.1)
elif(i == 1 and j ==1):
    if(actions == UP):
        return (i,j,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == LEFT):
        return (i,j,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == RIGHT):
        return (i,j,0.8),(i,j,0.1),(i,j,0.1)
elif (i == 1 and j == 2):
    if(actions == UP):
        return (i-1,j,0.8),(i,j,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i+1,j,0.8),(i,j,0.1),(i,j+1,0.1)
    elif(actions == LEFT):
        return (i,j,0.8),(i-1,j,0.1),(i+1,j,0.1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i-1,j,0.1),(i+1,j,0.1)
elif(i == 1 and j == 3):
    if(actions == UP):
        return (-2,-2,0.8),(-2,-2,0.1),(-2,-2,0.1)
    elif(actions == DOWN):
        return (-2,-2,0.8),(-2,-2,0.1),(-2,-2,0.1)
    elif(actions == LEFT):
        return (-2,-2,0.8),(-2,-2,0.1),(-2,-2,0.1)
    elif(actions == RIGHT):
        return (-2,-2,0.8),(-2,-2,0.1),(-2,-2,0.1)      
# 3rd row
elif(i == 2 and j == 0):
    if(actions == UP):
        return (i-1,j,0.8),(i,j,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j,0.1),(i,j+1,1,0.1)
    elif(actions == LEFT):
        return (i,j,0.8),(i-1,j,0.1),(i,j,0.1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i-1,j,0.1),(i,j,0.1)
elif (i == 2 and j == 1):
    if(actions == UP):
        return (i,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == LEFT):
        return (i,j-1,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i,j,0.1),(i,j,0.1)
elif(i == 2 and j == 2):
    if(actions == UP):
        return (i-1,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == LEFT):
        return (i,j-1,0.8),(i-1,j,0.1),(i,j,1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i-1,j,0.1),(i,j,0.1)
elif(i == 2 and j == 3):
    if(actions == UP):
        return (i-1,j,0.8),(i,j-1,0.1),(i,j,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j-1,0.1),(i,j,0.1)
    elif(actions == LEFT):
        return (i,j-1,0.8),(i-1,j,0.1),(i,j,0.1)
    elif(actions == RIGHT):
        return (i,j,0.8),(i-1,j,0.1),(i,j,0.1)

在值迭代函数中调用此函数：

def value_iteration():
U1 = [[0, 0, 0, 0],
      [0, 0, 0, 0],
      [0, 0, 0, 0]] 
while True:
    U=U1.copy()
    delta = 0
    for i in range(len(grid)):
        for j in range(len(grid[i])):
            U1[i][j] = max(sum(p*(R(k,l)+gamma*U[k][l]) for (k,l,p) in T(i,j,a)) for a in actlist)
            print(i,j,U1[i][j])
            delta = max(delta, abs(U1[i][j] - U[i][j]))
    if delta <= epsilon*(1 - gamma)/gamma:
        return U

问题是，for循环的前两次迭代与输出配合得很好

0 0
0 1
0 2
0 3
1 0
1 1
1 2 
1 3

但是随后代码因错误而停止

ValueError: too many values to unpack (expected 3)

2 个答案:

答案 0 :(得分：5)

看看** **中的元组，也许就是这个原因

# 3rd row
elif(i == 2 and j == 0):
    if(actions == UP):
        return (i-1,j,0.8),(i,j,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j,0.1),**(i,j+1,1,0.1)**
    elif(actions == LEFT):
        return (i,j,0.8),(i-1,j,0.1),(i,j,0.1)
    elif(actions == RIGHT):
        return (i,j+1,0.8),(i-1,j,0.1),(i,j,0.1)
elif (i == 2 and j == 1):
    if(actions == UP):
        return (i,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == DOWN):
        return (i,j,0.8),(i,j-1,0.1),(i,j+1,0.1)
    elif(actions == LEFT):
        return (i,j-1,0.8),(i,j,0.1),(i,j,0.1)
    elif(actions == RIGHT):
       return (i,j+1,0.8),(i,j,0.1),(i,j,0.1)

答案 1 :(得分：0)

正如@EdwardMinnix所提到的，您应该使用map，并且永远不要进行这种if / else构造。或者，如果有任何带有这些值的模式，请查看Stragety Pattern。

这将为您提供一些帮助：

...

VALUE_A = 0.8
VALUE_B = 0.1


def new_T(i, j, actions):
    result_map = {(0, 0, 1): ((i, i, VALUE_A), (i, i, VALUE_B), (i, j + 1, VALUE_B)),
              (0, 0, 2): ((i + 1, j, VALUE_A), (i, j, VALUE_B), (i, j + 1, VALUE_B)),
              (0, 0, 3): ((i, j, VALUE_A), (i, j, VALUE_B), (i + 1, j, VALUE_B)),
              (0, 0, 4): ((i, j + 1, VALUE_A), (i, i, VALUE_B), (i + 1, j, VALUE_B)),
              (0, 1, 1): ((i, i, VALUE_A), (i, j - 1, VALUE_B), (i, j + 1, VALUE_B)),
              (0, 1, 2): ((i, j, VALUE_A), (i, j - 1, VALUE_B), (i, j + 1, VALUE_B)),
              (0, 1, 3): ((i, j - 1, VALUE_A), (i, j, VALUE_B), (i, j, VALUE_B)),
              (0, 1, 4): ((i, j + 1, VALUE_A), (i, j, VALUE_B), (i, j, VALUE_B)),
              (0, 2, 1): ((i, j, VALUE_A), (i, j - 1, VALUE_B), (i, j + 1, VALUE_B)),
              (0, 2, 2): ((i + 1, j, VALUE_A), (i, j - 1, VALUE_B), (i, j + 1, VALUE_B)),
              (0, 2, 3): ((i, j - 1, VALUE_A), (i, j, VALUE_B), (i + 1, j, VALUE_B)),
              (0, 2, 4): ((i, j + 1, VALUE_A), (i, j, VALUE_B), (i + 1, j, VALUE_B))}

    return result_map.get((i, j, actions))


for i, j, action in itertools.product(range(4), range(4), range(1, 5)):
    print('%s %s %s' % (i, j, action))
    T_value = T(i, j, action)
    new_T_value = new_T(i, j, action)
    if T_value != new_T_value:
        raise AssertionError('Error! \nT:     %s \nNew T: %s' % (T_value, new_T_value))
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