I have tried with fillna() and to replace them with zeros if it has worked for me but I don't know how to replace it with a text. For example to change the NaN to 'None'
inmuebles.garage_cond.fillna('None')
inmuebles[inmuebles['garage_cond'].isna()]
But still the NaN
What is happening is that you are not really modifying said object. You have two options (I'm sure there are more, they are the ones that have occurred to me:
inmuebles.garage_cond = inmuebles.garage_cond.fillna('None')
inmuebles.garage_cond.fillna('None', inplace = True)
In this second, the argument
inplace = True
is what makes the function modify the object.