Question

我正在尝试在函数中使用字典值，并且我不断获得NameError。不知道我做错了什么。

import re

def main():
    sales_amount = get_amount()
    customer_ID = get_ID()
    discounts = read_discounts()
    calculate_discount(sales_amount, discounts)
    print(discount_percentage)
    #print (discounts)

def get_amount():
    return float(input("Enter total sales amount: "))

def get_ID():
    return float(input("Enter customer ID: "))

#function to read discount values, strip non-alphanumeric characters and add values to dictionary
def read_discounts():
    myFile = open('discount.txt', 'r')
    discountValues = {}

    #read and split first line
    firstLine = myFile.readline()
    firstLine = re.sub(r'\$','',firstLine)
    firstLine = re.sub(r'\%','',firstLine)
    firstLine = firstLine.split()
    #add values to dictionary
    discountValues['UpperLimit1'] = {firstLine[2]}
    discountValues['UpperLimit1'] = [ float(x) for x in discountValues['UpperLimit1'] ]
    discountValues['PercentDiscount1'] = {firstLine[4]}
    discountValues['PercentDiscount1'] = [ float(x) for x in discountValues['PercentDiscount1'] ]

    return (discountValues)

def calculate_discount(sales_amount,discounts):

    if sales_amount < discountValues[UpperLimit1]: 
        discount_percentage = discountValues[PercentDiscount1]

main()

这是追溯：

Traceback (most recent call last):
  File "C:\Users\Sam\Desktop\test.py", line 92, in <module>
main()
  File "C:\Users\Sam\Desktop\test.py", line 7, in main
calculate_discount(sales_amount, discountValues)
NameError: global name 'discountValues' is not defined

我已经尝试将字典名称作为参数传递给函数但产生相同的结果。另外我应该注意，我知道将文本文件读入字典的方法可能不是最佳的，但我现在想关注calculate_discount函数。

完全披露：这是作业。

Answer 1

discounts = read_discounts()
calculate_discount(sales_amount, discountValues)

您保存了discounts。使用它而不是discountValues。

再来一次：

def calculate_discount(sales_amount,discounts):

    if sales_amount < discountValues[UpperLimit1]: 
        discount_percentage = discountValues[PercentDiscount1]

始终使用名称。

您的read_discounts()方法似乎也有不正确的缩进。

Answer 2

在您的主要功能中，您正在使用变量“discountValues”：

calculate_discount(sales_amount, discountValues)

尚未声明，如果您打算使用gloabl，请在main（）函数中使用此语句。

def main():
    global discountValues
    ...

将字典传递给函数

2 个答案: