python写商品管理练习

#1、添加
    #1、商品名称
        #1、要从文件里面把所有的商品读出来
    #2、价格
        #1、写一个方法判断是否为合理的价格
    #3、数量
        #整数
   # product = {
   #      "爱疯差":{
   #        "price":999.98,
   #        "count":5
   #      },
   #    "car":{
   #      "price":32423432,
   #      "count":10
   #    }
   #  }
   # product['mac'] = {"price":9999,"count":5}

    # write(product)
    # 写入文件，最新的商品写进去
#2、删除
    # 1、商品名称
        # 1、要从文件里面把所有的商品读出来
# product = {
#     "爱疯差": {
#         "price": 999.98,
#         "count": 5
#     },
#
# }
# product.pop('car')

#3、查询
    # 1、要从文件里面把所有的商品读出来

FILENAME = 'product.json'
import json
import os
def get_product():
    with open(FILENAME,'a+',encoding='utf-8') as fr:
        fr.seek(0)
        content = fr.read()
        if content:
            res = json.loads(content)
        else:
            res = {}
    return res

def is_price(s):
    s=str(s)
    if s.count('.')==1:
        left,right = s.split('.')
        if left.isdigit() and right.isdigit():
            print('正小数')
            return float(s)
    elif s.isdigit():
        if int(s)>0:
            print('大于0的整数')
            return int(s)
    return False

def is_count(s):
    if s.isdigit():
        if int(s)>0:
            return int(s)

def write_product(product_dic):
    with open(FILENAME,'w',encoding='utf-8') as fw:
        json.dump(product_dic,fw,ensure_ascii=False,indent=4)

def add():
    all_products = get_product()
    pname = input('product_name:').strip()
    price = input('product_price:').strip()
    count = input('product_count:').strip()
    if not pname or not price or not count:#为空的时候干啥
        print('不能为空！')
    elif pname in all_products:
        print('商品已经存在')
    elif not is_price(price):
        print('价格不合法，只能是大于0的数值')
    elif not is_count(count):
        print('数量不合法！')
    else:
        all_products[pname] = {"price": float(price), "count": int(count)}
        write_product(all_products)
        print('添加商品成功')
        return
    return add()



    # if pname and price and count: #不为空的时候，我干啥。。

def delete():
    all_products = get_product()
    pname = input('product_name:').strip()
    if not pname :#为空的时候干啥
        print('不能为空！')
    elif pname not in all_products:
        print('商品不存在')
    else:
        all_products.pop(pname)
        write_product(all_products)
        print('删除商品成功')
        return
    return delete()

def show():
    all_products = get_product()
    if all_products:
        print(all_products)
    else:
        print('暂时还没有商品！')


choice = input('1、add\n'
               '2、delete\n'
               '3、show \n'
               '4、exit \n')

func_map = {"1":add,"2":delete,"3":show,"4":quit}
if choice in func_map:
    func_map[choice]()
else:
    print('输入有误！')


# if choice =="1":
#     add()
# elif choice=="2":
#     delete()
# elif choice=="3":
#     show()
# elif choice=="4":
#     quit("程序退出")
# else:
#     print('输入错误！')

# def a():
#     print('asdfdfs')
#
# b = a
# b()
#函数即变量