Nras - 2 months ago 26

Python Question

At some point in my workflow I end up with a regular pandas DataFrame with some columns and some rows. I want to export this DataFrame into a latex table,using

`df.to_latex()`

`import numpy as np`

import pandas as pd

# where I am

data = np.arange(15).reshape(3, 5)

df = pd.DataFrame(data=data, columns=['a', 'b', 'c', 'd', 'e'])

It looks like this:

`In [161]: df`

Out[161]:

a b c d e

0 0 1 2 3 4

1 5 6 7 8 9

2 10 11 12 13 14

I would like to group columns b and c, as well as d and e, but leave a alone. So my desired output should look like this.

`# where I want to be: leave column 'a' alone, group b&c as well as d&e`

multi_index = pd.MultiIndex.from_tuples([

('a', ''),

('bc', 'b'),

('bc', 'c'),

('de', 'd'),

('de', 'e'),

])

desired = pd.DataFrame(data, columns=multi_index)

It looks like this:

`In [162]: desired`

Out[162]:

a bc de

b c d e

0 0 1 2 3 4

1 5 6 7 8 9

2 10 11 12 13 14

In order to get there, i tried a simple reindex. This give me the desired shape, but all columns only got NaN as value.

`# how can use df and my multiindexreindex to multi column DataFrame`

result = df.reindex(columns=multi_index)

The result looks like described, correct indices but all NaN

`In [166]: result`

Out[166]:

a bc de

b c e e

0 NaN NaN NaN NaN NaN

1 NaN NaN NaN NaN NaN

2 NaN NaN NaN NaN NaN

How can I get my desired result?

Answer

Source (Stackoverflow)

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