如何将这个循环写成一个列表推导式?

Question

我有这样的代码

lista = list()
for dict_genres in df['genres']:
suport = list()
for genres in dict_genres:
suport.append(genres['id'])
lista.append(suport)

你怎么把它写成一个列表推导式呢?

Answer 1

1级list-comprehension

lista = []
for dict_genres in df['genres']:
lista.append([genres['id'] for genres in dict_genres])

2级列表理解

lista = [
[genres['id'] for genres in dict_genres]
for dict_genres in df['genres']
]

Answer 2

简写为:

lista = [[genres['id'] for genres in dict_genres] for dict_genres in df['genres']]

Answer 3

内循环

suport = [genres['id'] for genres in dict_genres]

所以整个就是

lista = [<snippet above> for dict_genres in df['genres']

使用列表推导构建列表的列表可能会变得有点不可读。