使用字典理解将列表转换为具有重复键的字典 [英] Convert list to dictionary with duplicate keys using dict comprehension
问题描述
大家好,
我正在尝试使用以下内容将长度为 2 的项目列表转换为字典:
I am trying to convert a list of length-2 items to a dictionary using the below:
my_list = ["b4", "c3", "c5"]
my_dict = {key: value for (key, value) in my_list}
问题是当列表中出现多个键时,只保留最后一个键及其值.
The issue is that when a key occurrence is more than one in the list, only the last key and its value are kept.
所以在这种情况下而不是
So in this case instead of
my_dict = {'c': '3', 'c': '5', 'b': '4'}
我明白了
my_dict = {'c': '5', 'b': '4'}
即使有重复的键,我如何保留所有键:值对.谢谢
How can I keep all key:value pairs even if there are duplicate keys. Thanks
推荐答案
对于字典中的一个键,您只能存储一个值.
For one key in a dictionary you can only store one value.
您可以选择将值作为列表.
You can chose to have the value as a list.
{'b': ['4'], 'c': ['3', '5']}
以下代码将为您做到这一点:
following code will do that for you :
new_dict = {}
for (key, value) in my_list:
if key in new_dict:
new_dict[key].append(value)
else:
new_dict[key] = [value]
print(new_dict)
# output: {'b': ['4'], 'c': ['3', '5']}
同样的事情可以用 setdefault
来完成.感谢@Aadit M Shah 指出
Same thing can be done with setdefault
. Thanks @Aadit M Shah for pointing it out
new_dict = {}
for (key, value) in my_list:
new_dict.setdefault(key, []).append(value)
print(new_dict)
# output: {'b': ['4'], 'c': ['3', '5']}
同样的事情可以用 defaultdict
来完成.感谢@MMF 指出.
Same thing can be done with defaultdict
. Thanks @MMF for pointing it out.
from collections import defaultdict
new_dict = defaultdict(list)
for (key, value) in my_list:
new_dict[key].append(value)
print(new_dict)
# output: defaultdict(<class 'list'>, {'b': ['4'], 'c': ['3', '5']})
您还可以选择将值存储为字典列表:
you can also chose to store the value as a list of dictionaries:
[{'b': '4'}, {'c': '3'}, {'c': '5'}]
以下代码将为您做到这一点
following code will do that for you
new_list = [{key: value} for (key, value) in my_list]
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