Check if a row in column is unique python Dataframe

I have the following Dataframe:

I want to check for every row in the column [‘id1’] if the value is unique

The output should be:

False
True
True
True
False

The first and the last are False because id 2 exists twice.

I used this method:

bool = df["id1"].is_unique but that checks if the whole column is unique. I want to check it for each row

>Solution :

df['id1'].map(~(df.groupby('id1').size() > 1))

Output

0    False
1     True
2     True
3     True
4    False
Name: id1, dtype: bool