Python--作业2--对员工信息文件，实现增删改查操作

函数练习：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:Huanglinsheng


def calc(x,y):
    res = x**y
    return res
c = calc(2,4)
print("计算结果是 %s" %c)

def stu_register1(name,age,country,course):
#def stu_register2(name,age,course,country="CN"):
    print("------注册学生信息------")
    print("姓名:",name)
    print("年龄:",age)
    print("国籍:",country)
    print("课程:", course)

stu_register1("hc",25,"USA","OPS1")
stu_register1("hls",24,"China","OPS2")
stu_register1("hht",20,"Vn","OPS3")

def stu_resgister3(name,age,*args):
    print(name,age,args)
stu_resgister3("huanglinsheng",22,"CN")

def stu_resgister4(name,age,*args,**kwargs):
    print(name,age,args,kwargs)
stu_resgister4("hucong",24,"CN","OPS",sex="MAN",province="hubei")


'''局部变量'''
name = "huanglinsheng"
def change_name(name):
    print("before change:",name)
    name =  "hls"
    print("after change",name)
change_name(name)
print("外部的name改变没？",name)


'''返回值'''
'''
要想获取函数的执行结果，就可以用return语句把结果返回
注意:
1. 函数在执行过程中只要遇到return语句，就会停止执行并返回结果，so 也可以理解为 return 语句代表着函数的结束
2. 如果未在函数中指定return,那这个函数的返回值为None 
'''


'''
递归
在函数内部，可以调用其他函数。如果一个函数在内部调用自身本身，这个函数就是递归函数
'''
def calc(n):
    print(n)
    if int(n/2) == 0:
        return n
    return calc(int(n/2))
calc(10)



'''递归函数实际应用案例，二分查找'''
data = [1, 3, 6, 7, 9, 12, 14, 16, 17, 18, 20, 21, 22, 23, 30, 32, 33, 35]

def binary_search(dataset,find_num):
    print(dataset)

    if len(dataset) > 1:
        mid = int(len(dataset)/2)
        if dataset[mid] == find_num:
            print("找到数字",dataset[mid])
        elif dataset[mid] > find_num:
            print("33[31;1m找的数在mid[%s]左面33[0m" %dataset[mid])
            return binary_search(dataset[0:mid],find_num)
        else:
            print("33[32;1m找的数在mid[%s]右面33[0m" % dataset[mid])
            return binary_search(dataset[mid+1:],find_num)
    else:
        if dataset[0] == find_num:
            print("找到数字啦", dataset[0])
        else:
            print("没的分了,要找的数字[%s]不在列表里" % find_num)

binary_search(data,17)

'''
内置参数详解 https://docs.python.org/3/library/functions.html?highlight=built#ascii 
'''

需求：

     1.可进行模糊查询，语法至少支持下面3种:

         1.1 select name,age from staff_table where age > 22

         1.2 select  * from staff_table where dept = IT

         1.3 查到的信息，打印后，最后面还要显示查到的条数 

     2.可创建新员工纪录，以phone做唯一键，staff_id需自增

     3.可删除指定员工信息纪录，输入员工id，即可删除

     4.可修改员工信息，语法如下:

        1.UPDATE staff_table SET dept= 无 where dept = IT

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:Huanglinsheng

import os

# 查询方式一：select * from data_staff.txt where age >= 22
# 查询方式二：select * from data_staff.txt where dept = "IT"
# 查询方式三：select * from data_staff.txt where enroll_date like "2013"

def Search():
    data=input("Input your select info:")
    data = data.split(' ')
    con = data[7]
    asp = data[5]
    count = 0
    with open('data_staff.txt','r',encoding='utf-8') as f:
        if asp == 'age':
            for line in f:
                if int(line.split(',')[2]) >= int(con):
                    print(line)
                    count +=1
        elif asp == 'dept':
            for line in f:
                if line.split(',')[4] in con:
                    print(line)
                    count +=1
        else:
            for line in f:
                if line.split(',')[5].split('-')[0] in con:
                    print(line)
                    count +=1
        print('查询结束，共查到符合条件的信息 %d 条' %count)

# 添加语法： name,age,phone,dept,enroll-date
def Add():
    data = input("请输入要添加员工的信息：")
    list_data = data.strip().split(',')
    list_all = []
    f = open('data_staff.txt','r+')
    for line in f:
        list_all.append(line.strip().split(',')[3])
    if list_data[2] in list_all:
        print("该用户已经存在！！")
    else:
        for line in f:
            f.write(line)
        staff_id = str(len(list_all) + 1)
        list_data.insert(0,str(staff_id))
        f.write('
')
        f.write(','.join(list_all))
        f.close()
        print("添加成功")

# 删除语法：delete from staff_table where staff_id = 12
def Delete():
    staff_id = input("输入您要删除员工的Staff_id:")
    staff_id = staff_id.strip().split(' ')[6]
    f = open('data_staff.txt','r')
    f1 = open('new_data_staff.txt','w')
    for line in f:
        in_list = line.split(',')
        if in_list[0] < staff_id:
            f1.write(line)
        elif in_list[0] > staff_id:
            in_list[0] = str(int(in_list[0]) - 1 )
            f1.write(','.join(in_list))
        else:
            continue
        f.close()
        f1.close()
        os.remove("data_staff.txt")
        os.rename('new_data_staff.txt','data_staff')
        print("删除成功！！")


#修改请输入（注意空格和没有引号）：UPDATE staff_table SET dept = IT where dept = 运维
def Change():
    data= input("请输入你要修改的信息：")
    old = data.split(' ')[5]
    new = data.split(' ')[9]
    f = open('data_staff.txt','r',encoding='utf-8')
    f1 = open('new_data_staff','w',encoding='utf-8')
    for line in f:
        if old in line:
            line = line.replace(old,new)
        f1.write(line)
    f.close()
    f1.close()
    os.remove('data_staff')
    os.rename('new_data_staff', 'data_staff')
    print('修改成功')


msg_dict = {
    '1':Search,
    '2':Add,
    '3':Delete,
    '4':Change,
    '5':'退出'
 }

while True:
    print("""
    1:查询
    2:添加
    3:删除
    4:修改
    5:退出
    """)
    choice = input("Input your choice:")
    if choice not in msg_dict:
        print("Input error!Pls Input one more time.")
        continue
    if int(choice) == 5:
        exit()
    else:
        msg_dict[choice]()

文本：data_staff.txt

1,Alex Li,22,13651054684,运维,2013-02-04
2,Jack Wang,20,13312331232,HR,2014-06-03
3,Mike Cao,20,15504231232,Sales,2013-05-06
4,Jack Chen,34,12404231232,HR,2011-02-01
5,Lu Haojie,21,15204231232,运维,2013-08-12