Question

不幸的是，我有一本很大的字典，里面有许多相同的键，而python不允许相同的键并且只打印最后一次出现的键，现在我发现的解决方案是将相同键的值更改为list或tuple。但是我不是能够找到一种自动的方法。我也想保留列表中值的顺序，因为我试图在下面的示例字典中提及它。我当前的字典看起来像这样：

dic = {
'a' : 2,
'a' : 1,
'b' : 2,
'a' : 4,
'a' : 3,
'b' : 1,
'b' : 2,
'c': 1
  }

现在根据解决方案应将其转换为：

dic = {
'a' : [2,1,4,3],
'b' : [2,1,2],
'c': 1
  }

谢谢。

Answer 1

您需要首先探查字典中是否已经包含您要为其添加新值的键。确定键是否已存在后，可以检查返回的值是单个数字还是数字列表，并采取相应的措施。

使用伪代码：

# Get current value associated with new key in dict.
# If returned value is None, add new value for key in question.
# Else If returned value is a list, append new value to list, store list for key in question
# Else, returned value was a single number; create a list of returned value and new value. Store list for key in question.

Python解决方案：

class DictUtil(object):
    """ A utility class that automates handling of key collisions for a dictionary object. """

    @staticmethod
    def add_to_dict(dict, new_key, new_value):
        # Get whatever currently exists within the dictionary for the given key.
        value_in_dict = dict.get(new_key)

        # If the value for the given key is None, there is no current entry, so we can add the new value.
        if value_in_dict is None:
            dict[new_key] =  new_value

        # If the value for a given key returned a list, append new value to list and re-store in dict.
        elif type(value_in_dict) in [list, tuple]:
            dict[new_key].append(new_value)

        # Otherwise, the get returned a single item. Make a list of the returned value and the new value and re-store.
        else:
            dict[new_key] = [value_in_dict, new_value]

def main():
    """ Entry point for an example script to demonstrate Dictutil functionality. """
    dict = {}

    # Populating values in dict using Dictutil method: add_to_dict:
    DictUtil.add_to_dict(dict, 'a', 2)
    DictUtil.add_to_dict(dict, 'a', 1)
    DictUtil.add_to_dict(dict, 'b', 2)
    DictUtil.add_to_dict(dict, 'a', 4)
    DictUtil.add_to_dict(dict, 'a', 3)
    DictUtil. add_to_dict(dict, 'b', 1)
    DictUtil.add_to_dict(dict, 'b', 2)
    DictUtil.add_to_dict(dict, 'c', 1)

    # Printing dictionary contents
    for key, value in dict.iteritems():
        print 'Key: %s \t Value: %s' % (key, value)


if __name__ == '__main__':
    main()

如何将相同键的值转换为列表

1 个答案: