我很讨厌显示的数据框：
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90 M8X Etobicoke The Kingsway , Montgomery Road , Old Mill North
91 M8Y Etobicoke Humber Bay , King's Mill Park , Kingsway Park ...
92 M8Z Etobicoke Kingsway Park South West , Mimico NW , The Que...
93 M9A Queen's Park Not assigned
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我想将第三列中“未分配”的每个条目的值更改为第二列中该条目对应的核心值。例如
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90 M8X Etobicoke The Kingsway , Montgomery Road , Old Mill North
91 M8Y Etobicoke Humber Bay , King's Mill Park , Kingsway Park ...
92 M8Z Etobicoke Kingsway Park South West , Mimico NW , The Que...
93 M9A Queen's Park Queen's Park
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