CODEWITHSUNDEEP
pythonpandasdataframemulti-index
thinwybk
thinwybk

Reputation: 4753

Reindex dataframe multiindex

I've a dataframe with row and column multiindex like this

            BLUB      BLA     
            A    B    C    D
sample
0      blub ...  ...
1      blub ...
2      blub
3      blub
4      blub
0      blub
1      blub
2      blub
...    ...

I'd like to reindex to this

            BLUB      BLA     
            A    B    C    D
sample
0      blub ...  ...
1      blub ...
2      blub
3      blub
4      blub
5      blub
6      blub
7      blub
...    ...

in a immutable manner (copying the dataframe, not changing it in place). How can I achieve this?

Upvotes: 1

Views: 62

Answers (1)

jezrael
jezrael

Reputation: 863801

Because MultiIndex in index you can create default index by first level of MultiIndex by DataFrame.reset_index and DataFrame.set_index:

df = (df.reset_index(level=1)
        .reset_index(drop=True)
        .set_index('level_1', append=True)
        .rename_axis(['sample', None]))

Or by MultiIndex.from_arrays:

mux = pd.MultiIndex.from_arrays([np.arange(len(df)), 
                                 df.index.get_level_values(1)], 
                                names=['sample', None])
df = df.set_index(mux)

Upvotes: 1

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