Set values on the diagonal of pandas.DataFrame

Question

I have a pandas dataframe I would like to se the diagonal to 0

import numpy
import pandas

df = pandas.DataFrame(numpy.random.rand(5,5))
df

Out[6]:
     0           


        

Answer 1

This solution is vectorized and very fast and unless the other suggested solution works for any column names and size of df matrix.

def pd_fill_diagonal(df_matrix, value=0): 
    mat = df_matrix.values
    n = mat.shape[0]
    mat[range(n), range(n)] = value
    return pd.DataFrame(mat)

Performance on Dataframe of 507 columns and rows

% timeit pd_fill_diagonal(df, 0)

1000 loops, best of 3: 145 µs per loop