Python - 创建字典列表

Question

I wanted to create a list of dictionaries in python. The usual way of creating a list worked for me. That is mylist = [{1:1},{2:2}]

However, when I tried creating it using a comprehension over range() function, mylist = [a:a for a in range(10)] I get syntax error.

But to my surprise, if I construct a set in the same manner, it works as expected. myset = {a:a for a in range(10)}

May I know why this is so? I am using Python3

Answer 1

I think you want something like this:

mylist = [{a:a} for a in range(10)]

You forgot about { and } .

In the second example, your myset is a dict, not a set:

In [8]: type(myset)
Out[8]: dict

In this example, { and } denote dictionary comprehension , not set comprehension.

Answer 2

您在列表理解中缺少字典创建：

mylist = [{a:a} for a in range(10)]