Pandas: concat dataframe with multi-index dataframe. Whats wrong?

Question

I'm trying to concat two dataframes, df y df_multindex:

df:

COL1   COL2    COL1   COL2
 10     a       20     a
 21     w2      21     w2

df_multindex:

  0      0     1      1
COL1   COL2   COL1   COL2
  1     a       1     a
 21     w2     21     w2

df_multinidex has to be concat below df.
df_multinidex has to remain their column name levels.
So the column names of the new dataframe has to be the multindex names from df_multindex

What I have tried:

 dftotal = pd.concat([df,df_multindex], axis = 0)

What i got was:

 TypeError: Expected tuple, got str

What I want is:

   0      0     1      1
COL1   COL2   COL1   COL2
 10     a      20     a
 21     w2     21     w2
  1     a       1     a
 21     w2     21     w2

Thank you

jezrael · Accepted Answer · 2020-11-27 09:57:05Z

1

You need MultiIndex in both DataFrames, so use:

df.columns = df_multindex.columns

dftotal = pd.concat([df,df_multindex])

answered Nov 27, 2020 at 9:57

jezrael

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