Python入门5（pandas中merge中的参数how）
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1 import pandas as pd 2 df1 = pd.DataFrame([[1,2,3],[1,10,20],[5,6,7],[3,9,0],[8,0,3]],columns=['x1','x2','x3']) 3 df2 = pd.DataFrame([[1,2],[1,10],[1,3],[4,6],[3,9]],columns=['x1','x4']) 4 print (df1) 5 print (df2) 6 df3 = pd.merge(df1,df2,how = 'left',on='x1') 7 print (df3) 8 df4 = pd.merge(df1,df2,how = 'right',on='x1') 9 print (df4) 10 df5 = pd.merge(df1,df2,how = 'inner',on='x1') 11 print (df5) 12 df6 = pd.merge(df1,df2,how = 'outer',on='x1') 13 print (df6)
