pandas not converting an object dtype to float64 even after error free execution of df.astype(‘float64’)

I have tried to convert an object dtype column to float64 using .astype('float64') It ran without raising any error, but when I check the dtype using .dtype or .dtypes it is showing that converted column again as object.

 real_estate['Age at time of purchase'].astype('float64')

164    67.0
153    61.0
133    56.0
132    56.0
179     NaN
       ... 
110    49.0
89     44.0
45     37.0
131    55.0
116    51.0
Name: Age at time of purchase, Length: 195, dtype: float64

real_estate.dtypes

Name                        object
Surname                     object
Age at time of purchase     object
Interval                    object
Y                          float64
M                          float64
D                          float64
Gender                      object
Country                     object
State                       object
dtype: object

Why is it not converting and why isn’t it giving any error?

also, real_estate['Age at time of purchase'].dtype this is giving me something that I haven’t expected. dtype('O') What does dtype('O') mean?

Answer

you can try like this

real_estate['Age at time of purchase']=real_estate['Age at time of purchase'].astype('float64')