"TypeError: 'int' object is not iterable" when moving itertools product inside function

Question

我正在尝试将 itertools.product 的用法移动到函数内部。当我尝试执行此操作时，出现以下错误消息，我不确定原因：

TypeError: 'int' object is not iterable

代码如下。在main函数中可以看到函数外使用的算法然后在函数中可以看到封装时使用的算法：

#!/usr/bin/env python

import itertools

def main():

    elements_specification = [[10, 20], [30, 40], [50, 60]]

    lists = [list(list_generated) for index, element_specification in enumerate(elements_specification) for list_generated in itertools.product(*elements_specification[:index + 1])]

    for list_configuration in lists:
        print(list_configuration)

    print("---")

    for list_configuration in list_element_combinations_variadic(
        [[10, 20], [30, 40], [50, 60]]
    ):
        print(list_configuration)

def list_element_combinations_variadic(
    elements_specification
    ):
    """
    This function accepts a specification of lists of elements for each place in
    lists in the form of a list, the elements of which are lists of possible
    elements and returns a list of lists corresponding to the combinations of
    elements of the specification with varying numbers of elements.

    For example, the list elements specification [[10, 20], [30, 40], [50, 60]]
    yields the following lists:

    [10]
    [20]
    [10, 30]
    [10, 40]
    [20, 30]
    [20, 40]
    [10, 30, 50]
    [10, 30, 60]
    [10, 40, 50]
    [10, 40, 60]
    [20, 30, 50]
    [20, 30, 60]
    [20, 40, 50]
    [20, 40, 60]
    """
    lists = [list(list_generated) for index, elements_specification in enumerate(elements_specification) for list_generated in itertools.product(*elements_specification[:index + 1])]
    return lists

if __name__ == "__main__":
    main()

Answer 1

基本上，您在 main 方法和另一个方法之间有错字。

在 main 中，element_specification 在 for

中是正确的

for index, element_specification in enumerate(elements_specification)

但在另一种方法中，您在 for

中有 elements_specification

for index, elements_specification in enumerate(elements_specification) 

恰好是该方法的参数名称，因此您要在列表理解中重新分配该参数

---

试试这个

lists = [list(list_generated) for index, element in enumerate(elements_specification) for list_generated in itertools.product(*elements_specification[:index + 1])]
return lists

或者因为您甚至不需要 enumerate 中的 element，只需使用 range。

lists = [list(list_generated) for index in range(len(elements_specification)) for list_generated in itertools.product(*elements_specification[:index + 1])]
return lists