python-保留 2 列中的唯一对

我有以下数据集：

'To':['Fabio Crestani', 'Tomasz Kusmierczyk', 'Simranjit Singh Sachar', 'Nicholas Diakopoulos', 'Omer F. Rana', 'Dimitrios Rafailidis', 'Nicholas Diakopoulos', 'Omer F. Rana','Dimitrios Rafailidis','Kjetil Nørvåg', 'Simranjit Singh Sachar','Tomasz Kusmierczyk', 'Kjetil Nørvåg','Dimitrios Rafailidis','Tomasz Kusmierczyk','Nicholas Diakopoulos','Dimitrios Rafailidis','Fabio Crestani', 'Simranjit Singh Sachar', 'Omer F. Rana','Pete Burnap', 'Omer F. Rana','Nasser Alsaedi', 'Omer F. Rana','Dimitrios Rafailidis', 'Fabio Crestani', 'Nicholas Diakopoulos', 'Nasser Alsaedi', 'Pete Burnap'],
'weight':[2,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]}

from_to_weight_df = pd.DataFrame(data=from_to_weight) 

我想排除from to=to from所在的行。为了更清楚地说明这一点，我希望得到以下输出：

from_to_weight = {'From':['Dimitrios Rafailidis','Dimitrios Rafailidis','Dimitrios Rafailidis','Dimitrios Rafailidis','Dimitrios Rafailidis','Fabio Crestani','Fabio Crestani','Tomasz Kusmierczyk','Tomasz Kusmierczyk','Kjetil Nørvåg','Simranjit Singh Sachar','Nicholas Diakopoulos','Nasser Alsaedi','Nasser Alsaedi','Pete Burnap'],'To':['Fabio Crestani','Tomasz Kusmierczyk','Simranjit Singh Sachar','Nicholas Diakopoulos','Omer F. Rana','Nicholas Diakopoulos','Omer F. Rana','Kjetil Nørvåg','Simranjit Singh Sachar','Kjetil Nørvåg','Nicholas Diakopoulos','Omer F. Rana','Pete Burnap','Omer F. Rana','Omer F. Rana'],'weight':[2,1,1,1,1,1,1,1,1,1,1,1,1,1,1]}

有什么想法吗？