1+ """
2+ 1148. Article Views I
3+ Solved
4+ Easy
5+ Topics
6+ Companies
7+ SQL Schema
8+ Pandas Schema
9+
10+ Table: Views
11+
12+ +---------------+---------+
13+ | Column Name | Type |
14+ +---------------+---------+
15+ | article_id | int |
16+ | author_id | int |
17+ | viewer_id | int |
18+ | view_date | date |
19+ +---------------+---------+
20+ There is no primary key (column with unique values) for this table, the table may have duplicate rows.
21+ Each row of this table indicates that some viewer viewed an article (written by some author) on some date.
22+ Note that equal author_id and viewer_id indicate the same person.
23+
24+ Write a solution to find all the authors that viewed at least one of their own articles.
25+
26+ Return the result table sorted by id in ascending order.
27+
28+ The result format is in the following example.
29+
30+ Example 1:
31+
32+ Input:
33+ Views table:
34+ +------------+-----------+-----------+------------+
35+ | article_id | author_id | viewer_id | view_date |
36+ +------------+-----------+-----------+------------+
37+ | 1 | 3 | 5 | 2019年08月01日 |
38+ | 1 | 3 | 6 | 2019年08月02日 |
39+ | 2 | 7 | 7 | 2019年08月01日 |
40+ | 2 | 7 | 6 | 2019年08月02日 |
41+ | 4 | 7 | 1 | 2019年07月22日 |
42+ | 3 | 4 | 4 | 2019年07月21日 |
43+ | 3 | 4 | 4 | 2019年07月21日 |
44+ +------------+-----------+-----------+------------+
45+ Output:
46+ +------+
47+ | id |
48+ +------+
49+ | 4 |
50+ | 7 |
51+ +------+
52+ """
53+ 54+ import pandas as pd
55+ 56+ def article_views (views : pd .DataFrame ) -> pd .DataFrame :
57+ unique_author_views = views [views ['author_id' ] == views ['viewer_id' ]].drop_duplicates ('author_id' )
58+ ordered_author_views = unique_author_views .sort_values ('author_id' )
59+ return ordered_author_views [['author_id' ]].rename (columns = {'author_id' : 'id' })
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