从字典列表中获取值列表? [英] Get a list of values from a list of dictionaries?

问题描述

我有一个字典列表，我需要从字典中的给定键中获取值的列表(所有字典都具有相同的键).

I have a list of dictionaries, and I need to get a list of the values from a given key from the dictionary (all the dictionaries have those same key).

例如，我有:

l = [ { "key": 1, "Val1": 'val1 from element 1', "Val2": 'val2 from element 1' }, 
      { "key": 2, "Val1": 'val1 from element 2', "Val2": 'val2 from element 2' }, 
      { "key": 3, "Val1": 'val1 from element 3', "Val2": 'val2 from element 3' } ]

我需要得到1、2、3.

I need to get 1, 2, 3.

我当然可以用:

v=[]
for i in l:
    v.append(i['key'])

但是我想找到一种更好的方法.

But I would like to get a nicer way to do so.

推荐答案

使用简单的

Using a simple list comprehension (if you're sure every dictionary has the key):

In [10]: [d['key'] for d in l]
Out[10]: [1, 2, 3]

否则，您需要首先检查是否存在:

Otherwise you'll need to check for existence first:

In [11]: [d['key'] for d in l if 'key' in d]
Out[11]: [1, 2, 3]

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