类型错误：只能将列表（不是“元组”）连接到列表（（Python））

Question

在小脚本中运行以下代码时，出现以下错误：

Traceback (most recent call last):
  File "/Users/PeterVanvoorden/Documents/GroepT/Thesis/f_python_standalone/python_files/Working_Files/testcase.py", line 9, in <module>
    permutations_01.determin_all_permutations()
  File "/Users/PeterVanvoorden/Documents/GroepT/Thesis/f_python_standalone/python_files/Working_Files/permutations_01.py", line 8, in determin_all_permutations
    config.permutations = [[1] + x for x in config.permutations]
TypeError: can only concatenate list (not "tuple") to list

代码：

import itertools
import config

def determin_all_permutations():
    L = list(xrange(config.number))
    List = [x+2 for x in L]
    config.permutations = list(itertools.permutations(List,config.number))
    config.permutations = [[1] + x for x in config.permutations]


def determin_lowest_price_permutation():
    length = len(L)
    a = 1
    while a <= length:
        point_a = L[a]
        point_b = L[a+1]

# Array with data cost connecting properties will exist of:
# * first column = ID first property [0]
# * second column = ID second property [1]
# * third column = distance between two properties [2]
# * forth column = estimated cost [3]

        position  = 0
        TF = False

        if TF == False:
            if point_a == config.properties_array[position][0] and point_b == config.properties_array[position][1] and TF == False:
                config.current_price = config.current_price + config.properties_array[position][3]
                config.current_path = config.current_path + [config.properties_array[position][2]]
                TF = True

            else:
                position += 1

        else:
            position = 0
            TF = False

我不明白为什么会发生这个错误。当我测试第 8 行时

config.permutations = [[1] + x for x in config.permutations]

在正常情况下，通过在 Shell 中列出一个列表，例如：

List = [1,1,1],[1,1,1]
([1,1,1],[1,1,1])
List = [[0] + x for x in List]
List
([0,1,1,1],[0,1,1,1])

它有效，但是在方法中使用完全相同的代码时，我收到有关添加元组的错误... [1] 不是列表吗？

有人可以帮助我吗？

谢谢！

Answer 1

在您在 shell 上执行的内容中，List由列表[1,1,1]和 组成[1,1,1]，而不是元组。因此，做List = [[0] + x for x in List]工作没有错误。

在您的代码中，list(itertools.permutations(List,config.number))返回一个元组列表，例如：

[(2, 4, 8, 5, 11, 10, 9, 3, 7, 6), (2, 4, 8, 5, 11, 10, 9, 6, 3, 7),...]

这解释了错误。

这样做：

config.permutations = [[1] + list(x) for x in config.permutations]

解决了这个问题。