Help with merging dataframes

Deep Learning
1

Hi Pandas experts.

Here’s a dataframe, mel1, indexed by float64 (a time):
image

Here’s a second dataframe, silences, with the same kind of index:
image
I merely want to interleave the two dataframes in order of the onset index. That should not be hard, right? But I have read the docs until my eyeballs are falling out. Can you please help?

1 Like
2

import pandas as pd

pd.merge lets you do a join by setting how {‘left’, ‘right’, ‘outer’, ‘inner’}. If you want the join to be on the index, left_index and right_index arguements are what you are looking for.

If you just want to make a dataframe that is the length of both dataframes combined (ie insert the second one in the first). pd.concat([df1,df2]) should do that.

If you need to then sort by the index, then https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.sort_index.html

2 Likes
3

Hi Enzo. Thanks for responding. pd.concat() duplicated columns when the two dataframes both had column names in common. But df1.append(df2), listed in related functions, combined columns with the same name, just as I wanted. df.sort_index(inplace=True) then interleaved the rows properly.

Thanks again. Malcolm

1 Like