Pandas —— 唯一值unique( ),计数值value_counts( )及成员资格isin( )
唯一值In[141]:obj=pd.Series(['c','a','d','a','a','b','b','c','c','c'])In[142]:obj.unique()Out[142]:array(['c','a','d','b'],dtype=object)计数值In[143]:obj.value_counts()Out[143]:c4a3b2d1dtype:int64成员资格In[144