Objekt in INT64 Pandas
>>> df['purchase'].astype(str).astype(int)
Stupid Salmon
>>> df['purchase'].astype(str).astype(int)
# convert Series
my_series = pd.to_numeric(my_series)
# convert column "a" of a DataFrame
df["a"] = pd.to_numeric(df["a"])
df.astype(int)