Replicate/duplicate first value (column A) over all columns in entire row

Does anyone know, how to get from this:

to this:

Try using slice assignment:

df[:] = df.iloc[0, 0]

Or if you want to specify the Rate index:

>>> df[:] = df.loc['Rate'].iloc[0]
>>> df
       A   B   C   D   E   F   G
Rate  RS  RS  RS  RS  RS  RS  RS
>>>