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문제
Table Activities:
+-------------+---------+
| Column Name | Type |
+-------------+---------+
| sell_date | date |
| product | varchar |
+-------------+---------+There is no primary key (column with unique values) for this table. It may contain duplicates.
Each row of this table contains the product name and the date it was sold in a market.
Write a solution to find for each date the number of different products sold and their names.
The sold products names for each date should be sorted lexicographically.
Return the result table ordered by sell_date.
https://leetcode.com/problems/group-sold-products-by-the-date/description/?lang=pythondata
예시
Input:
Activities table:
+------------+------------+
| sell_date | product |
+------------+------------+
| 2020-05-30 | Headphone |
| 2020-06-01 | Pencil |
| 2020-06-02 | Mask |
| 2020-05-30 | Basketball |
| 2020-06-01 | Bible |
| 2020-06-02 | Mask |
| 2020-05-30 | T-Shirt |
+------------+------------+
Output:
+------------+----------+------------------------------+
| sell_date | num_sold | products |
+------------+----------+------------------------------+
| 2020-05-30 | 3 | Basketball,Headphone,T-shirt |
| 2020-06-01 | 2 | Bible,Pencil |
| 2020-06-02 | 1 | Mask |
+------------+----------+------------------------------+
Explanation:
For 2020-05-30, Sold items were (Headphone, Basketball, T-shirt), we sort them lexicographically and separate them by a comma.
For 2020-06-01, Sold items were (Pencil, Bible), we sort them lexicographically and separate them by a comma.
For 2020-06-02, the Sold item is (Mask), we just return it.문제 풀이
import pandas as pd
def categorize_products(activities: pd.DataFrame) -> pd.DataFrame:
result = activities.groupby('sell_date')['product'].agg(
# 고유 제품 수 계산
num_sold='nunique',
# 고유 제품 목록을 ','로 구분한 문자쳘을 products column으로
products= lambda x: ','.join(sorted(x.unique()))).reset_index()
return result파이썬을 독학하시는 분들에게 도움이 되길 바라며,
혹 더 좋은 방법이 있거나 오류가 있다면 편하게 말씀 부탁드립니다.
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