How can I fill an empty dataframe with zero in pandas? Fillna not working-CodePudding

A dataframe is being created by a process and sometimes the process returns an empty dataframe with no values at all. In that case I want the dataframe to be filled with zeroes for all the columns. I've tried output_df.fillna(value=0, inplace=True) but it doesn't work. The dataframe just remains empty.

CodePudding user response：

To replace all values with 0, you can use:

df.loc[:] = 0

If you really have no rows and want to add one:

df.loc[0] = 0

CodePudding user response：

If has empty DataFrame only with columns names possible solution for add 0 is use DataFrame.reindex by some list for new indices:

df = pd.DataFrame(columns=['a', 'b'])

df = df.reindex([0, 1, 2], fill_value=0)
print (df)
   a  b
0  0  0
1  0  0
2  0  0

df = pd.DataFrame()

df = df.reindex(index=[0, 1, 2], columns=list('ab'), fill_value=0)
print (df)
     a    b
0  0.0  0.0
1  0.0  0.0
2  0.0  0.0