참고 : https://rfriend.tistory.com/521
#1. pd.cut()을 이용해서 continuous -> categorical 변환.
#2. pd.cut(X, bins, labels)
#2.1 X : dataframe, bins : bins=[미포함,포함], labels=['a']
#2.2 source data
print(df_age_error)
#2.3 age categorization
age_cate = [18,29,39,49,59,69,80]
age_cate_name = ['20','30','40','50','60','70']
df_age_error['age_gp'] = pd.cut(df_age_error['age'], bins=age_cate, labels=age_cate_name)
print(df_age_error)
