python - Keep rows in df1 based on indices in in df2

Question

I have two data frames like this:

df_1

index	index_col	values
0	5	4.4
1	7	5.6
2	12	8.2
...	...	...

question from:https://stackoverflow.com/questions/65951102/keep-rows-in-df1-based-on-indices-in-in-df2

Answer 1

Use Index.isin with boolean indexing:

df3 = df2[df2.index.isin(df1['index_col'])]

Or DataFrame.merge:

df3 = (df2.merge(df1[['index_col']], left_index=True, right_on='index_col')
          .drop('index_col', axis=1))