pandas in drop_duplicates usage

pandas.DataFrame.drop_duplicates(self, subset=None, keep='first', inplace=False)

　The default is a subset of all columns, but you can specify your own

data=pd.DataFrame({'A':[2,2,3,2],'b':[2,3,2,2],'c':[2,2,1,3],'d':[1,1,3,3]})
data

　　

data = data.drop_duplicates()
data

data.drop_duplicates (subset = [ 'A' , 'b'], keep = 'last', inplace = True) # subset contrast parameter which is represented by columns 
print (data)