如何在python字典中使用列表作为键

2019年8月3日 334次阅读

我想使用如下字典：

示例：{[8,16]：[[1,2,4,8],8],[16,24]：[[1,2,3,4,8,12],12]}

8和16是将要输入的两个数字,我需要构建如上所述的字典.

使用setdefault,我可以在字典中创建值列表,但不能为键创建列表

以下是我的代码：

#!/usr/bin/env python
"""
        This Program calculates common factors between two Numbers , which 
        is stored on a list and also greatest common factor is also computed.
        All this is stored in a dictionary
        Example: { '[n1, n2]': [[Commonfac1(n1,n2), Commonfac2(n1,n2)....Commonfacn(n1,n2)],GreatestCommonFactor] }
"""
def Factors(number):
        result = []
        for i in range(1, number+1):
                if (number % i) == 0:
                        result.append(i)

        return result

def Common_Factors(n1, n2):
        result = []
        for element in n1:
                if element in n2:
                        result.append(element)

        return result

def greatest_common_factor(common_factors):
        count = 0
        length = len(common_factors)
        current_largest = common_factors[count]
        for i in common_factors:
                count += 1
                if count <= length -1:
                        if current_largest < common_factors[count]:
                                current_largest = common_factors[count]
        return current_largest


def main():
        n1 = 8
        n2 = 16
        result1 = Factors(n1)
        result2 = Factors(n2)

        CF = Common_Factors(result1, result2)

        GCF = greatest_common_factor(CF)

        dict = {}

        dict.setdefault([n1, n2], []).append(CF)
        print dict

if __name__ == '__main__':
        main()

当我运行上面的程序时,我得到以下错误：

$python math74.py 
Traceback (most recent call last):
  File "math74.py", line 58, in <module>
    main()
  File "math74.py", line 54, in main
    dict.setdefault([n1, n2], []).append(CF)
TypeError: unhashable type: 'list'

关于我如何实现上述任何提示. ？

澄清更多：
{[8,16]：[[1,2,4,8],8],[16,24]：[[1,2,3,4,8,12],12]}

8,16是两个数字,它们是用户输入,1,2,4,8是常见因子,8是最大公因数.

最佳答案 列表可能不是您想要的,因为：

 1.列表是可变的.这意味着它可以更改(删除/添加/修改)其值.例如：

>>> testList = [1,5]
>>> d = {"myList": testL}
>>> d
{'myList': [1, 5]}
>>> testList.append(53)
>>> d
{'myList': [1, 5, 53]}
>>>

如您所见,可以更改列表,并且键必须是唯一的.
对于不可变的数组类型,Python有一个元组.一旦定义了元组,就无法修改它.这意味着,您也可以将其用作目录中的键：

>>> myTuple = (4, 5)
>>> myDict = {myTuple: "here is the value"}
>>> myDict
{(4, 5): 'here is the value'}
>>> myTuple.append(9)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'append'
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