Python 使用整型值而非绝对值时的代码

这是一个错误，“costofkeg”的输入是一个绝对值，回溯显示：

Traceback (most recent call last):
  File "C:\Users\Zico\Desktop\GrossSP.py", line 23, in <module>
    portioncost = (costofkeg/(kegsize/(portionsize*0.568)))
TypeError: unsupported operand type(s) for /: 'str' and 'float'

代码将完美地工作

下面是需要更改的代码，但我不知道要更改什么

kegsize = int(input('Please enter keg size. Litres: '))

costofkeg = input('Please enter cost of keg. GBP: ')

abv = input('Please enter Alcohol by Volume. %: ')

gp = int(input('Please enter Gross Profit Percentage. %: '))

print('These are the Portion Size options (imperial measurements), 1/3, 1/2, 2/3, 1.')
portionsize = eval(input('Please choose Portion Size: '))
print ('')
if portionsize not in ['1/3' , '1/2' , '2/3' , '1']:
    print('Thank you, find your inputs below\n')


print ('Keg Size', kegsize, 'Litres')
print ('Cost of Keg', costofkeg, 'GBP')
print ('Alcohol by Volume', abv, '%')
print ('Gross profit percentage', gp, '%\n')


portioncost = (costofkeg/(kegsize/(portionsize*0.568)))
pc = format(portioncost, '.2f')
print('Portion Cost', pc, 'GBP')

netsp = 100*(portioncost/(100-gp))
nsp = format(netsp, '.2f')
print ('Net Selling Price', nsp, 'GBP')

grosssp = (netsp*1.2)
gsp = format(grosssp, '.2f')
print ('Gross Selling Price', gsp, 'GBP')

---

我在理解你的问题时遇到了一个问题，所以我将用一般术语来写这篇文章

如果要计算至少有一个数字（float或int）的表达式，则所有内容都必须是数字

所以

将引发错误，因为

test

是字符串

要将内容转换为数字数据类型，可以执行以下操作：

testNum = input("Enter a number that will be converted to a string")
testNum = eval(testNum)

或

对某些人来说，如果表达式中的一项是浮点或字符串，那么它们都必须是浮点或字符串。检查以确保每个值都是数字数据类型。此外，您不能分割字符串

所以就围绕着,

costofkeg = input('Please enter cost of keg. GBP: ')

---

使用

float（）

会引发错误，因为您希望使用不受支持的字符串进行除法（正如回溯告诉您的那样）

所以要考虑的是：

portioncost = (costofkeg/(kegsize/(portionsize*0.568)))

如果你看一下变量的定义，你会发现第一个变量不是一个数字（一个

int

或一个

float

）是

costofkeg

因此，您应该将用户的输入转换为合适的数据类型。因为这显然是一个价格，所以我建议使用

浮动

。所以改变

costofkeg = input('Please enter cost of keg. GBP: ')

变成

costofkeg = float(input('Please enter cost of keg. GBP: '))

此外，在转换数据类型时，应考虑捕获错误。那么，如果用户输入一个文本字符串作为价格，然后将其传递给

float（）

，会发生什么情况呢？为了考虑到这一点，我建议使用块来处理错误。如果您为每个输入使用多个函数来整理代码，那么如果在将输入转换为所需数据类型时发生错误，您可以自己调用这些函数

这看起来像这样（只是一个使用您已有代码的简短示例片段）：

portionsize

的输入可能会成为另一个问题。将其作为函数编写可能如下所示：

def ask_portionsize(string):
    val = ask_float(string)
    if val not in [1/3 , 1/2 , 2/3 , 1]:
        print('Thank you, find your inputs below\n')
    else:
        try:
            val = float(val)
        except ValueError as e:
            ask_portionsize()
        else:
            return val

portionsize = ask_portionsize('Please choose Portion Size: ')

---

要使代码同时处理整数和绝对值，请将这些更改应用于代码

kegsize = int(input('Please enter keg size. Litres: '))

costofkeg = float(input('Please enter cost of keg. GBP: '))

abv = input('Please enter Alcohol by Volume. %: ')

gp = int(input('Please enter Gross Profit Percentage. %: '))

print('These are the Portion Size options (imperial measurements), 1/3, 1/2,     2/3, 1.')
portionsize = eval(input('Please choose Portion Size: '))
print ('')
if portionsize not in ['1/3' , '1/2' , '2/3' , '1']:
    print('Thank you, find your inputs below\n')


print ('Keg Size', kegsize, 'Litres')
print ('Cost of Keg', costofkeg, 'GBP')
print ('Alcohol by Volume', abv, '%')
print ('Gross profit percentage', gp, '%\n')

注意'（portionsize'前面的float，这是因为您不能分割字符串，所以我必须浮动变量

portioncost = (costofkeg/(kegsize/float(portionsize*0.568)))
pc = format(portioncost, '.2f')
print('Portion Cost', pc, 'GBP')

netsp = 100*(portioncost/(100-gp))
nsp = format(netsp, '.2f')
print ('Net Selling Price', nsp, 'GBP')

grosssp = (netsp*1.2)
gsp = format(grosssp, '.2f')
print ('Gross Selling Price', gsp, 'GBP')

---

你能告诉我什么是正确的，什么是错误的版本吗？没有正确的版本。这是因为当我尝试使用整数时，代码会工作，但只有在一定程度上，我这样说，因为当我尝试任何不是整数的东西时，我会得到上面显示的回溯。我会怎么做ke表示无论输入的数字是整数还是带小数的数字，代码都可以工作。提前谢谢。那么我如何将“portionsize”变量更改为此行中的字符串。portioncost=（costofkeg/（kegsize/（portionsize*0.568）））为什么要将其更改为字符串？您不能拆分字符串。您可以通过

str（portionsize）

执行此操作，非常有意义，谢谢。请参阅下面我的答案。：）

def ask_int(string):
    try:
        val = int(input(string))
    except ValueError as e:
        print('Invalid format. Your input was not an integer.')
        ask_int(string)
    else:
        return val

def ask_float(string):
    try:
        val = float(input(string))
    except ValueError as e:
        print('Invalid format. Your input was not a float')
        ask_int(string)
    else:
        return val

kegsize = ask_int('Please enter keg size. Litres: ')
costofkeg = ask_float('Please enter cost of keg. GBP: ')
abv = ask_float('Please enter Alcohol by Volume. %: ')
gp = ask_int('Please enter Gross Profit Percentage. %: ')

def ask_portionsize(string):
    val = ask_float(string)
    if val not in [1/3 , 1/2 , 2/3 , 1]:
        print('Thank you, find your inputs below\n')
    else:
        try:
            val = float(val)
        except ValueError as e:
            ask_portionsize()
        else:
            return val

portionsize = ask_portionsize('Please choose Portion Size: ')

kegsize = int(input('Please enter keg size. Litres: '))

costofkeg = float(input('Please enter cost of keg. GBP: '))

abv = input('Please enter Alcohol by Volume. %: ')

gp = int(input('Please enter Gross Profit Percentage. %: '))

print('These are the Portion Size options (imperial measurements), 1/3, 1/2,     2/3, 1.')
portionsize = eval(input('Please choose Portion Size: '))
print ('')
if portionsize not in ['1/3' , '1/2' , '2/3' , '1']:
    print('Thank you, find your inputs below\n')


print ('Keg Size', kegsize, 'Litres')
print ('Cost of Keg', costofkeg, 'GBP')
print ('Alcohol by Volume', abv, '%')
print ('Gross profit percentage', gp, '%\n')

portioncost = (costofkeg/(kegsize/float(portionsize*0.568)))
pc = format(portioncost, '.2f')
print('Portion Cost', pc, 'GBP')

netsp = 100*(portioncost/(100-gp))
nsp = format(netsp, '.2f')
print ('Net Selling Price', nsp, 'GBP')

grosssp = (netsp*1.2)
gsp = format(grosssp, '.2f')
print ('Gross Selling Price', gsp, 'GBP')