Value	Description
`"first"`	All duplicates are marked as `True` except the first one.
`"last"`	All duplicates are marked as `True` except the last one.
`False`	All duplicates are marked as `True`.

By default, keep="first".

Return value

A Series where True represents duplicate rows.

Examples

Consider the following DataFrame:


        
        
            
                
                
                    df = pd.DataFrame({"A":[1,2,1], "B":[3,4,3]})
df
                
            
               A  B
0  1  3
1  2  4
2  1  3

Here, the 1st and 3rd rows are duplicate.

Specifying the keep parameter

first

To mark all duplicate rows except the first one:


        
        
            
                
                
                    df.duplicated()   # or explicitly set keep="first"
                
            
            0    False
1    False
2     True
dtype: bool

last

To mark all duplicate rows except the last one:


        
        
            
                
                
                    df.duplicated(keep="last")
                
            
            0     True
1    False
2    False
dtype: bool

False

To mark all duplicate rows as True:


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