So I have a data frame called df. It looks like this.

I want to sum up the columns and divide the sum of the columns by the sum of the rows. So for example: row 1, column 0: (1 4 7)/(1 2 3) row 2, column 0: (1 4 7)/(4 5 6)

so on and so forth.

so that my final result is like this.

How do I do it in python using pandas and dataframe?

CodePudding user response：

You can also do it this way:

import numpy as np
a = df.to_numpy()
b = np.divide.outer(a.sum(0),a.sum(1)) 
# divide is a ufunc(universal function) in numpy.
# All ufunc's support outer functionality
out = pd.DataFrame(b, index=df.index, columns=df.columns)

output:

     0      1     2
0  2.0  2.500  3.00
1  0.8  1.000  1.20
2  0.5  0.625  0.75

CodePudding user response：

You can use the underlying numpy array:

a = df.to_numpy()
out = pd.DataFrame(a.sum(0)/a.sum(1)[:,None],
                   index=df.index, columns=df.columns)

output:

     0      1     2
0  2.0  2.500  3.00
1  0.8  1.000  1.20
2  0.5  0.625  0.75