Python error Series object is not callable

Question

This line:

df['ln_returns'] = np.log(df['Close_mid']/df['Close_mid'](1))

Gives the following error:

'Series' object is not callable 

Answer 1

Try this:

df['ln_returns'] = np.log(df['Close_mid']/df['Close_mid'])

df['Close_mid'](1)) doesn't seem to be doing anything