需求：

3、写一个商品管理的程序

功能1：添加商品

功能2：删除商品信息

功能3：修改商品信息

功能4：查看商品，输入all，查看所有商品，输入单个商品名称查看单个商品信息

商品格式存在文件中，goods.json

例子是在goods.py

import json

FILE_NAME = ‘goods.json‘

def read_product():

with open(FILE_NAME,‘a+‘,encoding=‘utf-8‘) as fr:

fr.seek(0)

result = fr.read()

if result:

return json.loads(result)

return {}

def write_product(product):

with open(FILE_NAME,‘w‘,encoding=‘utf-8‘) as fr:

json.dump(product,fr,ensure_ascii=False,indent=4)

def get_product_name():

for i in range(3):

name = input("请输入商品名称：").strip()

if name:

return name

else:

print(‘商品名称不能为空‘)

else:

quit("错误次数过多")

def show():

name = get_product_name()

product = read_product()

if name == ‘all‘:

print(product)

elif product.get(name):

print("商品信息是%s"%product.get(name))

else:

print(‘商品不存在！‘)

def delete():

name = get_product_name()

product = read_product()

if product.get(name):

product.pop(name)

print("商品已经被删除")

write_product(product)

else:

print(‘商品不存在！‘)

def check_count(count:str):

if count.isdigit():

if int(count)>0:

return int(count) #1

#None

def check_price(price:str):

count = check_count(price)

if count:

return count

else:

if price.count(‘.‘)==1 and price.replace(‘.‘,‘‘).isdigit():

return float(price) if float(price)>0 else None

def add():

name = get_product_name()

price = input("price:").strip()

count = input("count:").strip()

color = input("color:").strip()

price = check_price(price)

count = check_count(count)

if price and count and color :

product = read_product()

if product.get(name):

print(‘无法添加‘)

else:

d = {"price":price,‘count‘:count,‘color‘:color}

product[name] = d

print("添加成功！")

write_product(product)

else:

print("价格/数量/颜色不合法")

def modify():

name = get_product_name()

price = input("price:").strip()

count = input("count:").strip()

color = input("color:").strip()

price = check_price(price)

count = check_count(count)

if price and count and color :

product = read_product()

if product.get(name):#商品存在可以修改

d = {"price": price, ‘count‘: count, ‘color‘: color}

product[name] = d

print("修改成功！")

write_product(product)

else:

print(‘商品不存在！‘)

else:

print("价格/数量/颜色不合法")

choice = input("请输入：1、添加2、修改、3、查看4、删除、other、退出").strip()

if choice == "1":

add()

elif choice == "2":

modify()

elif choice=="3":

show()

elif show()=="4":

delete()

else:

quit()

choice = input("请输入：1、添加2、修改、3、查看4、删除、other、退出：").strip()

func_map = {‘1‘:add,‘2‘:modify,‘3‘:show,‘4‘:delete}

if choice in func_map:

func_map.get(choice)()

else:

quit("退出程序！")