商品程序

import json

FILENAME = 'product.json'

def op_file_json(file_name,dic=None):
    if dic:
        with open(file_name,'w',encoding='utf-8') as fw:
            json.dump(dic,fw,ensure_ascii=False,indent=4)
    else:
        with open(file_name,'a+',encoding='utf-8') as fr:
            fr.seek(0)
            content = fr.read()
            if content:
                result = json.loads(content)
            else:
                result = {}
            return result

def is_price(s): #形式参数
    s = str(s)
    if s.count('.') == 1:#这个是判断正小数
        left,right = s.split('.')  #1.74  ['1','74']
        if left.isdigit() and right.isdigit() and right>'0':
            return True
    if s.isdigit() and s >'0':#判断是否为大于0 的整数
        return True
    return False

def add_product():
    all_product = op_file_json(FILENAME) #获取到所有的产品
    name = input('name:').strip()
    count = input('count:').strip() #s1 s3 1.s
    price = input('price:').strip()
    if name and count and price:
        if count.isdigit() and count >'0' and is_price(price):
            if name in all_product:
                print('商品已经存在了')
            else:
                all_product[name]={"price":price,"count":count}
                op_file_json(FILENAME,all_product)
                print('添加成功！')
        else:
            print('数量、价格不合法')
    else:
        print('必填项不能为空！')

def modify_product():
    all_product = op_file_json(FILENAME) #获取到所有的产品
    name = input('name:').strip()
    count = input('count:').strip() #s1 s3 1.s
    price = input('price:').strip()
    if name and count and price:
        if count.isdigit() and count >'0' and is_price(price):
            if name in all_product:
                all_product[name] = {"price": price, "count": count}
                op_file_json(FILENAME, all_product)
                print('修改成功！')
            else:
                print('商品不存在！')
        else:
            print('数量、价格不合法')
    else:
        print('必填项不能为空！')

def delete_product():
    all_product = op_file_json(FILENAME) #获取到所有的产品
    name = input('name:').strip()
    if not name:
        print('没有输入商品名称！')
    elif name not in all_product:
        print('商品不存在！')
    else:
        all_product.pop(name)
        op_file_json(FILENAME,all_product)
        print('删除成功！')

def show_product():
    all_product = op_file_json(FILENAME) #获取到所有的产品
    name = input('请输入商品名称，什么也不输入的话，就代表查看所有的商品:').strip()
    if name!='' and name in all_product:
        print(all_product[name])
    elif name=='':
        print(all_product)
    else:
        print('商品不存在！')


func_dic = {"1":add_product,"2":modify_product,"3":delete_product,"4":show_product}

for i in range(3):
    choice = input('请输入你的选择！'
                   '1、添加商品'
                   '2、修改商品'
                   '3、删除商品'
                   '4、查看商品:').strip()
    if choice in func_dic:
        func_dic[choice]()
    else:
        print('输入选项错误！')

#函数即变量