建立一个帮助公司存储和分析销售数据的程序

Question

我必须写一个程序，为一家公司写一个文件，并分析销售数据

• request_countryname函数必须验证用户输入的长度是否至少为2个字符
• request_sales功能必须接受2个参数（产品和国家），请求用户输入该国家/地区每个产品的总销售额，并验证金额是否为数字和非负数
• request_data函数将使用上述函数向用户迭代请求国家名称，并询问用户是否要添加其他国家。用户完成后，程序将显示添加到文件中的记录数。程序将写入一个文件名（sales_data.txt）
• analyze_数据功能将计算每种产品的每个国家/地区的平均销售额、每种产品类型的总销售额以及总销售额

我在使用analyze_data函数时遇到问题。我不断收到一个错误，说我的request_data函数中的一些变量未定义。我相信这是因为这些变量（如软件）是局部定义的，而不是全局定义的。我尝试在analyze_data函数的开头调用request_data函数来调用我在文件中写入的信息，但仍然得到一个错误。我也不确定我是否正确使用累加器来计算每种产品类型的总数

我该如何解决这个问题

#Request country name from user
#Country name must be at least 2 characters long 
def request_countryname():
    
    character_length = 2             
    while True: 
        country = input("Please enter the country's name: ")   
        if len(country) < character_length or not country.isalpha():
            print("Name must be at least 2 characters.")
        else:
            return country 


#Request total sales for each product type for the user's country
#Input must be numeric and non negative
def request_sales(product, country_name):
    
    flag = -1
    while flag < 0: 
        sales = input("Please enter the total sales for " + product + " in " + country_name + ": $ ")
        try:
           sales = float(sales)
        except ValueError:
            print("Amount must be numeric")
        else: 
            if sales < 0 :
                print("Amount must be numeric and and non-negative. ")
            else:
                flag = 1
    return sales 

 
    
#Iteratively requests country names from the user and asks for totals
#Once the user finishes inputting countries, program will store data to a file 
#Program will display total number of records added 
def request_data(sales_data):
    
    sales_data = open(sales_data, "w")
    count = 0
    software_accumulator = 0
    hardware_accumulator = 0
    accessories_accumulator = 0
    
    again = "y"
    while again == "y" or again == "Y":
            country_name = request_countryname()
            software = request_sales("software", country_name)
            hardware = request_sales("hardware", country_name)
            accessories = request_sales("accessories", country_name)

            #Write data to file 
            sales_data.write(country_name + '/n')
            sales_data.write(software + '/n')
            sales_data.write(hardware + '/n')
            sales_data.write(accessories + '/n')
            
            count += 1   
            software_accumulator += software 
            hardware_accumulator += hardware
            accessories_accumulator += accessories
            
           
            #Request country names from user
            again = input("Do you want to add another country? (Enter y/Y for Yes: ")
           
            #Displays total number of records added 
            print(count, " record(s) successfully added to file")
            
            
    sales_data.close()
    
           
#Calculates and displays information 
def analyze_data(sales_data):
    
    sales_data = open(sales_data, "r")
    sales_data = request_data(sales_data)
    
    #Calculates total software of all country inputs 
    total_software = software_accumulator  
    
    #Calculates total hardware of all country inputs
    total_hardware = hardware_accumulator
    
    #Calculates total accessories of all country inputs
    total_accessories =  accessories_accumulator
    
    #Calcuates average software
    average_software = total_software / count
    
    #Calcuates average hardware
    average_hardware = total_hardware / count
    
    #Calcuates average accessories
    average_accessories = total_accessories / count

    #Calculates total sales 
    total_sales = total_software + total_hardware + total_accessories
        
    #Prints and displays calculations 
    print("----------------------------")
    print()
    print("Average software sales per country: $ ", format(average_software, ',.2f'))
    print("Average hardware sales per country: $ ", format(average_hardware, ',.2f'))
    print("Average accessories sales per country: $ ", format(average_accessories, ',.2f'))

    print()
    print("Total software sales: $ ", format(total_software, ',.2f'))
    print("Total hardware sales: $ ", format(total_hardware, ',.2f'))
    print("Total accessories sales: $ ", format(total_accessories, ',.2f'))

    print()
    print("Total sales: $ ", format(total_sales, ',.2f'))

#Defines main function
def main():    
    request_data("sales_data.txt")    
    analyze_data("sales_data.txt")
    
#Calls main function     
main()  

Answer 1

你的直觉是正确的，这与变量所在的范围有关，注意定义变量的位置，一旦退出函数，该函数范围内的所有变量都将消失。不要使用全局变量，而是从函数返回所需的值

我建议也使用IDE进行开发，当您访问一个不在范围内（即未定义）的变量时，它们会告诉您—PyCharm或VSCode都是高度可访问的

IDE说函数没有返回值

IDE表示未定义变量