[pandas] 182. Duplicate Emails

reference
https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.duplicated.html
https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.duplicated.html

문제 : https://leetcode.com/problems/duplicate-emails/description/

중복된 email만 출력

duplicated

input value에 대해, 중복여부를 return한다.
subset으로 column을 지정할 수 있고, keep 으로 deupicate를 mark 한다.
first -> Mark duplicates as True except for the first occurrence.
last -> Mark duplicates as True except for the last occurrence.
Flse -> Mark all duplicates as True.

df.duplicated()
0    False
1     True
2    False
3    False
4    False
dtype: bool

df.duplicated(keep=False)
0     True
1     True
2    False
3    False
4    False
dtype: bool

drop_duplicates

duplicate rows 를 제거한다.

Code

def duplicate_emails(person: pd.DataFrame) -> pd.DataFrame:
    df = person[person.duplicated(subset=["email"])][["email"]]
    df = df.drop_duplicates()
    return df