leetcode : 511. Game Play Analysis I

leetcode : 511. Game Play Analysis I

• [leetcode : 511. Game Play Analysis I]

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다이어그램

erDiagram
    Player {
        int player_id pk
        int device_id
        date event_date pk
        int games_played
    }

목표

Write a solution to find the first login date for each player.

유저 별 가장 로그 빠른 시간 찾기

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문제 풀이

MySQL

--  Solution 1
SELECT PLAYER_ID, MIN(EVENT_DATE) AS FIRST_LOGIN
FROM ACTIVITY
GROUP BY PLAYER_ID

• Solution 1
  • 각 그룹별 최소 날짜 출력하기

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Pandas

#  Solution 1
def game_analysis(activity: pd.DataFrame) -> pd.DataFrame:

    activity['event_date'] = pd.to_datetime(activity['event_date'])
    answer = activity.groupby('player_id')['event_date'].min().reset_index()
    answer.rename(columns={'event_date':'first_login'}, inplace=True)
    return answer

#  Solution 2
def game_analysis(activity: pd.DataFrame) -> pd.DataFrame:
    answer = activity.groupby('player_id').agg(
        first_login = ('event_date','min')
    ).reset_index()
    return answer

#  Solution 3
def game_analysis(activity: pd.DataFrame) -> pd.DataFrame:
    activity.sort_values(by = 'event_date', inplace = True)
    df = activity.drop_duplicates(subset ='player_id', keep='first')
    df.drop(columns = ['device_id','games_played'], inplace=True)
    df.rename(columns = {'event_date':'first_login'}, inplace=True)

    return df

• Solution 1,2 : group by + min
  • groupby로 묶은 후, event date 최소값을 가져와주기.
• Solution 3 : sort_values + drop_duplicates
  • 정렬 이후 한 번의 순회로도 풀이가 가능하다.
  • 날짜별 정렬을 한 후, 중복 아이디가 나오면 최소 날짜가 아니므로 제거해준다.

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코멘트

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