【对比Python】外键关联2
任务：找出部门经理最年轻的部门
Python
| 1 | import pandas as pd |
| 2 | import datetime |
| 3 | emp_file = "E:/txt/EMPLOYEE.txt" |
| 4 | manager_file = "E:/txt/DEPARTMENT.txt" |
| 5 | emp_info = pd.read_csv(emp_file,sep='\t') |
| 6 | manager_info = pd.read_csv(manager_file,sep='\t') |
| 7 | manager_join = pd.merge(manager_info,emp_info,left_on='MANAGER',right_on='EID') |
| 8 | today = datetime.datetime.today().year |
| 9 | arr = pd.to_datetime(manager_join['BIRTHDAY']) |
| 10 | manager_join['AGE'] = today-arr.dt.year |
| 11 | min_age = manager_join['AGE'].min() |
| 12 | young = manager_join[manager_join['AGE']==min_age]['DEPT'] |
| 13 | print(young) |
集算器
| A | |
| 1 | =file("E:/txt/EMPLOYEE.txt").import@t() |
| 2 | =file("E:/txt/DEPARTMENT.txt").import@t() |
| 3 | =A2.join(MANAGER,A1:EID,~:manager) |
| 4 | =A3.minp(manager.(age(BIRTHDAY))).manager.DEPT |
同样是外键对象化的应用。