熊猫有条件地将数据帧添加到另一个数据帧

Question

from pandas import DataFrameimport pandas as pddf_1 = pd.DataFrame(    {        'Horses':["Horse1","Horse2","Horse3"],        'Age':[2,5,3],        'Price':["$100,000","$80,000","$60,000"],        'Weight':["180g","140kg","240kg"]})  df_2 = pd.DataFrame(    {        'Horses':["Horse4","Horse1","Horse5"],        'Age':[4,3,2],        'Price':["$75,000","$35,000","$120,000"],        'Weight':["210kg","110kg","197kg"]})  df_final = pd.DataFrame(    {        'Horses':["Horse1","Horse2","Horse3","Horse4","Horse5"],        'Age':[2,5,3,4,2],        'Price':["$100,000","$80,000","$60,000","$75,000","$120,000"],        'Weight':["180g","140kg","240kg","210kg","197kg"]})如何从前两个数据帧 bf_1 和 bf_2 创建 df_final DataFrame ？我该如何编码这个条件：如果输入“Horse1”，它会像上面一样被擦除，否则它会被添加到底部

Answer 1

使用 combine_first

df_1.set_index('Horses',inplace=True)

df_1=df_1.combine_first(df_2.set_index('Horses')).reset_index()

df_1

   Horses  Age     Price Weight

0  Horse1  2.0  $100,000   180g

1  Horse2  5.0   $80,000  140kg

2  Horse3  3.0   $60,000  240kg

3  Horse4  4.0   $75,000  210kg

4  Horse5  2.0  $120,000  197kg