如果索引在另一个数据框中而不列出列，熊猫会替换所有列值吗？

Question

I have two dataframes ( df1, df3 ) with 12 columns and values for the next 12 months. I want to replace the values of df1 if index is in df2 with values of df3 . The two dataframes ( df1, df3 ) comes automatically with 12-month rolling columns.

df1 = pd.DataFrame(np.array([[100, 200, 300, 100, 150, 200, 220, 230, 300, 340, 250, 300], [400, 500, 600, 200, 300, 100, 150, 200, 220, 230, 300, 340], [150, 200, 220, 230, 300, 340, 200, 150, 90, 200, 200, 150]]),
               columns=['March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December', 'January', 'February'], 
               index= ['AB', 'CD', 'EF'])


df3 = pd.DataFrame(np.array([[200, 120, 150, 200, 300, 150, 150, 200, 320, 230, 250, 120], [450, 400, 500, 100, 300, 200, 150, 200, 320, 230, 250, 100], [300, 250, 190, 300, 200, 150, 200, 120, 150, 200, 300, 100]]),
               columns=['March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December', 'January', 'February'], 
               index= ['AB', 'CD', 'EF'])


data = ['AB', 'RE', 'AF'] 
df2 = pd.DataFrame(data, columns = ['Lookup'])

Expected output would be for index 'AB' the values of df3 for the next 12 months and for 'CD' and 'EF' the values of df1 .

Answer 1

After trying and google I came across the following code which perfectly works.

matches = df1.index.isin(df2.Lookup)
df1.loc[matches, :] = df3.loc[matches, :]