python - 嵌套列表或集合理解的正确语法

Question

想象一下这个对象:

my_obj = {
    'Episodes' : [
        {'Tags' : ['one','two','three']},
        {'Tags' : ['three','four','five']}
            ]
        }

我想创建一组标签:

tags = set(tag for tag in e['Tags'] for e in my_obj['Episodes'])

但是，它不起作用，因为未定义 e。我该怎么做？？

Answer 1

tags = set(tag  for e in my_obj['Episodes'] for tag in e['Tags'])

你需要改变顺序，先拿到 e...:)