在列表的每个字典中添加一个元素(列表理解) [英] Add an element in each dictionary of a list (list comprehension)

问题描述

我有一个词典列表，并且想为该列表的每个元素添加一个键. 我试过了:

I have a list of dictionaries, and want to add a key for each element of this list. I tried:

result = [ item.update({"elem":"value"}) for item in mylist ]

但是update方法返回None，所以我的结果列表中没有None.

but the update method returns None, so my result list is full of None.

result = [ item["elem"]="value" for item in mylist ]

返回语法错误.

推荐答案

您不必担心构造新的词典列表，因为对更新后的词典的引用与对旧词典的引用相同:

You don't need to worry about constructing a new list of dictionaries, since the references to your updated dictionaries are the same as the references to your old dictionaries:

 for item in mylist:
    item.update( {"elem":"value"})

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