换行符ch后出现意外字符

Question

我在这一行的连续字符错误后得到一个意外字符

 print (\t,"Order total $",format(total, "10.2"),\n\t,"Discount    $",format(disc,"10.2"),\n\t,"Amount Due $",format (due, "10.2"),sep="")

有人能告诉我这意味着什么以及如何修复它吗？ 谢谢

def finddiscount(quantity):
        if quantity >= 1 and quantity <= 9:
            discount = 0
        elif quantity >= 10 and quantity <= 19:
            discount = .2
        elif quantity >= 20 and quantity <= 49:
            discount = .30
        elif quantity >= 50 and quantity <= 99:
            discount = .40
        elif quantity >= 100:
            discount = .50
    def calctotal(quantity, price):
        disc = (price*quantity)*finddiscount(quantity)
        total = (price*quantity)
        due = (price*quantity)-(price*quantity)*dicount
        print (\t,"Order total $",format(total, "10.2"),\n\t,"Discount    $",format(disc,"10.2"),\n\t,"Amount Due $",format (due, "10.2"),sep="")
    def main():
        quantity = int(input("How many packages where purchased?"))
        price = float(input("How much is each item?"))
        calctotal(quantity, price)
    main()

Answer 1

Ashwini的回答解释了为什么你的代码会给出错误。

但有一个简单得多的方法。不要像这样打印由逗号分隔的字符串，只需将这些字符串放在一起：

print("\tOrder total $", format(total, "10.2"),
      "\n\tDiscount    $", format(disc, "10.2"),
      "\n\tAmount Due $", format(due, "10.2"), sep="")

（我还修复了所有内容，使之适合80列屏幕，这是一个标准，一方面，它实际上在StackOverflow之类的东西上是可读的；另一方面，它使您的代码实际上并没有按照您希望的方式排列……）

在这种情况下，最好使用三个单独的print调用。那么您首先不需要那些\n字符：

print("\tOrder total $", format(total, "10.2"), sep="")
print("\tDiscount    $", format(disc, "10.2"), sep="")
print("\tAmount Due $", format(due, "10.2"), sep="")

同时，由于您已经在使用format函数，因此学习format方法时应该不会遇到任何问题，这会使事情更加简单。同样，您可以使用三个单独的语句，但在这种情况下，可能更容易读取多行（三重引号）字符串：

print("""\tOrder total ${:10.2}
\tDiscount    ${:10.2}
\tAmount Due ${:10.2}""".format(total, disc, due))

有关所有这些的详细信息，请参阅Fancier Output Formatting教程部分。

Answer 2

你忘了在这行的许多项目上使用引号：

print ("\t","Order total $",format(total, "10.2"),"\n\t","Discount    $",format(disc,"10.2"),"\n\t","Amount Due $",format (due, "10.2"),sep="")
        ^                                           ^                                          ^

另一种格式化方法是使用str.format如下：

print ("\tOrder total $ {:10.2}\n\tDiscount    ${:10.2}\n\tAmount Due ${:10.2}".format(total, disc, due))