Question

嗨，我正在尝试创建一个程序，该程序要求数字在末尾求平均值，并在输入空格时给出平均值。我的代码如下：

number_of_numbers = 0
sum_of_numbers = 0
zero_number = 0
while number_of_numbers > -1:
    decimal_number = input('Input a number: ')
    if decimal_number == (''):
        decimal_number = zero_number
    else:
        decimal_number = float(decimal_number)
    number_of_numbers = number_of_numbers + 1
    sum_of_numbers = sum_of_numbers + decimal_number
    if decimal_number == '':
        break
print((sum_of_numbers + zero_number) / number_of_numbers)

但它总是说空白是一个字符串。我试图通过为空白分配一个新变量来解决该问题，该变量算作零，但由于某种原因，我一直收到错误消息。出于某种原因，它也使我被0除。

任何帮助将不胜感激谢谢

Answer 1

将break语句放在第一个if中，并使用if not decimal_number:而不是检查''，因为空字符串是虚假的，因此在布尔上下文中它们被认为是错误的

还要在尝试除法之前检查number_of_numbers是否为0。

number_of_numbers = 0
sum_of_numbers = 0
zero_number = 0
while number_of_numbers > -1:
    decimal_number = input('Input a number: ')
    if not decimal_number:
        decimal_number = zero_number
        ## number_of_numbers = 1
        break
    else:
        decimal_number = float(decimal_number)
    number_of_numbers = number_of_numbers + 1
    sum_of_numbers = sum_of_numbers + decimal_number
if number_of_numbers == 0:
    print('Cannot Divide by zero!')
else:
    print((sum_of_numbers + zero_number) / number_of_numbers)

Answer 2

当您碰到空白处时，您正试图停止。那是' '，而不是''。您正在测试''，这不是一个空格，它只是一个长度为0的字符串。

更好的解决方案是从输入中剥离所有空格，然后然后检查其后是否为空字符串（例如，除了空格之外，什么都没有）。您将替换行

if decimal_number == (''):

使用

if decimal_number.strip() == (''):

.strip()方法只是从字符串的前面和后面删除空格。

Answer 3

我不确定在输入空格''时是否要增加number_of_numbers个数字（您可以在代码中执行此操作）。这就是为什么我提供两个版本。

1）在空白处增加number_of_numbers：

number_of_numbers = 0
sum_of_numbers = 0
while True:
    decimal_number = input('Input a number: ')
    if decimal_number == '':
        number_of_numbers += 1
        break            
    try:
        sum_of_numbers += float(decimal_number)        
        number_of_numbers += 1
    except ValueError:
        print('Wrong Input. Try Again')
        continue
print(sum_of_numbers / number_of_numbers)

2）不要在空白处增加number_of_numbers（需要检查sum_of_numbers中的零）：

number_of_numbers = 0
sum_of_numbers = 0
while True:
    decimal_number = input('Input a number: ')
    if decimal_number == '':
        break        
    try:
        sum_of_numbers += float(decimal_number)        
        number_of_numbers += 1
    except ValueError:
        print('Wrong Input. Try Again')
        continue
if number_of_numbers == 0:
    print('No values to compute Average')
else:
    print(sum_of_numbers / number_of_numbers)

希望有帮助。

ValueError：在Python 3中无法将字符串转换为浮点错误

3 个答案: